No abstract

This prospective study investigates the frequency of patent foramen ovale (PFO), venous air embolism (VAE) and paradoxical air embolism (PAE) by transoesophageal echocardiography (TOE) in neurosurgical patients operated on in the sitting position. The risk of PAE after exclusion of PFO is assessed. A PFO was identified by pre-operative TOE and VAE and PAE by continuous intraoperative TOE. Sixty-two patients were divided into two groups, 22 patients were studied in group 1 (posterior fossa surgery) and group 2 (cervical surgery) contained 40 patients. Pre-operative TOE demonstrated a PFO in 5 of the 22 patients in group 1 (23%). Patients with proven PFO were excluded from the sitting position. Two further patients of this group (12% of 17 patients), in whom a PFO had been excluded pre-operatively, nevertheless had PAE, air occurring in all cavities of the heart. In group 2 the incidence of PFO was 4 out of 40 patients (10%). No PAE was observed in this group. Three morphological types of VAE with different haemodynamic and ventilation changes were demonstrated. VAE was observed in 76% of all posterior fossa operations and in 25% of cervical laminectomies. We conclude that a pre-operative search for PFO is mandatory considering its incidence of 23% in group 1 and of 10% in group 2, and the risk of PAE. If a PFO is detected, the sitting position should be avoided. A residual risk for PAE remains despite exclusion of PFO because the reliability of TOE is limited. TOE is the method of choice for detecting VAE and PAE.

The purpose of this prospective study was to identify the incidence of a distinct central anticholinergic syndrome following routine anaesthesia. For 2 months, all inpatients aged more than 15 years scheduled for elective procedures and cared for in the recovery room were investigated for symptoms of the syndrome. Patients with neuropsychiatric disease or other disorders that could alter consciousness were excluded. Prolonged action of anaesthetics or relaxants, respiratory depression and metabolic disorder were ruled out before making the diagnosis. Out of 962 patients (366 men, 596 women), 18 (4 men, 14 women) developed the syndrome. The difference between men and women was not statistically significant. Six out of 60 women developed the syndrome after a hysterectomy with or without adnectomy/oophorectomy, and this high incidence was significantly different from that observed after all other procedures in women (P = 0.003) or all other gynaecological procedures (P = 0.013). The reason for this is unknown. In six of the 18 cases, untreated prolonged somnolence lasted for more than 2 h. All patients woke up after an injection of physostigmine, but six of them relapsed into somnolence and needed a second, and in one case a third, injection. The findings of the study emphasize that, when there is delayed recovery from anaesthesia, the diagnosis of central anticholinergic syndrome should be considered if other accessible causes for that condition have been excluded.

No abstract

In a randomized double-blind study, midazolam 0.1 mg kg-1 i.m. was compared with diazepam 0.2 mg kg-1 and placebo as premedication for patients undergoing urological interventions under spinal anaesthesia. The sedative and anxiolytic effects of midazolam were evident 5-10 min after administration, and were maximum between 30 and 90 min. After this, rapid recovery was observed. More than 90% of the patients receiving midazolam were totally or partially amnesic for the procedures in the induction room and the operation theatre. Amnesia was not seen in the patients receiving diazepam or placebo and, in contrast to midazolam, diazepam had almost no sleep-inducing effect. In a few patients, the depth of sleep achieved with midazolam 0.1 mg kg-1 was such that co-operation was impaired.