Comparative evaluation of propofol or methohexitone as the sole anaesthetic agent for microlaryngeal surgery.

Propofol or methohexitone was given to the same twenty patients on two separate occasions during total intravenous anaesthesia for microlaryngeal surgery. With propofol the quality of induction was superior. Fewer patients required supplementation.

Impedance cardiography for cardiac output measurement: an evaluation of accuracy and limitations.

The Kubicek thoracic cylinder model of impedance cardiography (IC) for measuring beat-by-beat stroke volume (SV) was evaluated in controlled studies using the electromagnetic flowmeter (FM) as the reference technique. Assuming the validity of the Kubicek equation for stroke volume calculation, IC stroke volume was found to be a linear function of EM values at any one haematocrit over a wide range of SV, but the slope of the relationship fell as haematocrit fell. Experiments using the same equation in dogs, in which blood resistivity in vivo (rho tau) was made the dependent variable, and the EM-derived value was used for stroke volume, showed that rho tau was almost constant over a wide range of haematocrits.

Hypoxaemia during postoperative recovery using continuous pulse oximetry.

Continuous pulse oximetry monitoring was used to determine the incidence of hypoxaemia (arterial oxygen saturation less than or equal to 90%) occurring in the first hour of postoperative recovery. Of 107 patients studied, hypoxaemia was recorded in 80%. Twenty-eight (26%) of these patients had saturations below 80%.

Suprabulbar and bulbar integration of ventilation and ear vascular control during thermoregulation in the rabbit.

Suprabulbar and bulbospinal integration of cardiorespiratory responses to cold and heat stress was studied in groups of normal, thalamic and pontine rabbits. The animals sat in an airconditioned environmental chamber in which ambient temperature (TA) was maintained sequentially at 22 degrees C, 12 degrees C, 22 degrees C and 35 degrees C, with an accuracy of +/- 1 degree C. Neither thalamic nor pontine rabbits could maintain core temperature in cold or heat.

Role of central nervous system monoamines in cardiopulmonary effects of Althesin in rabbit and man.

The steroid induction agent, Althesin, infused intravenously in light anesthetic doses in otherwise unsedated man (84 micrograms kg-1 min-1) and rabbit (140 micrograms kg-1 min-1) causes similar autonomic and somatic effects. In the rabbit, the rise in heart rate (mainly due to central vagal blockade) and the selective depressant effects on respiratory rate are independent of CNS 5-hydroxytryptamine and noradrenaline. The rise in arterial pressure and the fall in hindlimb conductance is dependent on CNS 5-hydroxytryptamine and noradrenaline synthesizing neurons, which are probably arranged in series.