Plasma adrenaline and noradrenaline concentrations were measured in 10 consecutive patients during functional endoscopic sinus surgery (FESS). Surgery was preceded by nasal packing with 5 ml 2% cocaine solution, followed by infiltration with 1:80,000 adrenaline and 2% lignocaine. All patients showed a marked rise in plasma adrenaline concentration within 4 min of commencing infiltration, which was not related to the patient's sex, age, weight, the total amount injected, nor the amount injected into the nose. Surgeons should be aware of this marked, but unpredictable, systemic absorption of locally infiltrated vasoconstrictors. Pulse and ECG monitoring should be considered mandatory for such procedures, even when surgery is performed under local anaesthesia.

Previous studies on oxygen consumption (VO2) during weaning from mechanical ventilation assumed that an increase in VO2 (delta VO2) reflected oxygen consumption by respiratory muscles (VO2RESP), and proposed delta VO2 as a weaning predictor. We measured VO2 CO2 production (VCO2) and plasma catecholamines in 20 short-term ventilated patients during weaning by SIMV and CPAP. delta VO2 as a percentage of VO2 during spontaneous ventilation (delta VO2%) ranged from 4.8% to 41.5%. VCO2 also increased and correlated with VO2. Plasma adrenaline and noradrenaline increased significantly to levels known to produce considerable increases in metabolic rate. Mean arterial pressure and heart rate concomitantly increased, but spontaneous minute ventilation decreased. Thus, since the increased plasma catecholamines are calorigenic, the assumption that delta VO2 represents VO2RESP is incorrect. Although mean delta VO2% of successfully weaned patients was significantly less than that of failure-to-wean patients, the wide scatter of individual values in the latter group excludes delta VO2% as an accurate weaning predictor.

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Plasma catecholamine concentrations were measured after vasoconstrictor solutions were administered either by instillation (Moffett's method) or by submucosal infiltration in twenty patients undergoing elective nasal surgery. Following infiltration with 4.4 ml of 1:80,000 adrenaline and 2% lignocaine, plasma adrenaline concentrations increased by 44.3 times to a peak of 9.9 nmol.l-I (1813 pg.ml-I) within one minute. In contrast the peak level of adrenaline in the patients receiving Moffett's solution containing 1 ml of 1:1,000 adrenaline was 1.27 nmol.l-I (232 pg.ml-I) occurring 10 minutes after instillation of the solution. The difference in the adrenaline concentrations between the groups was statistically significant (P < 0.01). The lack of sympathoneuronal response was confirmed by simultaneous measurements of plasma noradrenaline concentrations, which did not change significantly. The operative field was subjectively assessed to be better in the infiltrated patients and the mean operating time and measured blood loss were less in this same group of patients.