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SUMMARY1. Forearm blood flow was measured bilaterally in healthy young male and female volunteers, in the basal state and after upper-arm occlusion of arterial or venous blood flow for 1-20 min. The investigations were repeated after pre-treatment with drugs affecting vascular prostaglandins and/or adenosine.2. Simultaneous arterial occlusion in one arm and venous occlusion in the contralateral arm for up to 20 min elicited a considerable reactive hyperaemia in the arm subjected to arterial occlusion, but completely failed to elevate the post-occlusive flow in the arm subjected to venous occlusion above the pre-occlusive level.3. When the arterial occlusion was increased from 1 to 20 min there was a progressive increase in the subsequent reactive hyperaemia, up to 30 ml 100 ml tissue-1. The time dependence following 1-3 min of arterial occlusion was based on a facilitation of the peak post-occlusive flow, while prolongation of the arterial occlusion from 3 to 20 min augmented the reactive hyperaemia mainly by increasing its duration.4. Inhibition of prostaglandin synthesis with ibuprofen reduced the total reactive hyperaemia following 3-5 min of arterial occlusion by up to 70 %. This attenuation was due both to a reduction of peak post-occlusive flow and to a shortening of the duration of the post-occlusive hyperaemia.5. The adenosine receptor antagonist theophylline reduced the reactive hyperaemia following 5 min of arterial occlusion by about 35 %. Combined treatment with ibuprofen and theophylline did not reduce the reactive hyperaemia more than either drug alone.6. Infusion of dipyridamole, a drug which inhibits the elimination of adenosine, reinforced the reactive hyperaemia by about 45 %. This effect of dipyridamole was completely inhibited by administration of theophylline, and also by ibuprofen.7. Plasma levels of adenosine, hypoxanthine and uric acid were maintained during the reactive hyperaemia, indicating increased production of purines during or immediately after the ischaemia.

The laparoscopic operating technique is being applied increasingly to a variety of intra-abdominal operations. Intra-abdominal gas insufflation, i.e. pneumoperitoneum (PP), is then used to allow surgical access. The haemodynamic effects of PP in combination with different body positions have not been fully examined. Eleven patients without signs of cardiopulmonary disease were studied before and during laparoscopic cholecystectomy under propofol-fentanyl anaesthesia with controlled ventilation. Swan-Ganz and radial arterial catheterization were used to determine haemodynamic data in the horizontal position, with a 15-20 degree head-down tilt and a 15-20 degree head-up tilt. The measurements were repeated after insufflation of carbon dioxide to an intraabdominal pressure of 11-13 mmHg, as well as during surgery. The ventricular filling pressures of the heart were strictly dependent on body position. PP in the horizontal position increased pulmonary capillary wedge pressure by 32% (P < 0.01), central venous pressure by 58% (P < 0.01), and mean arterial pressure by 39% (P < 0.01). When PP was combined with a head-down tilt, there was a further increase in filling pressures by approximately 40% (P < 0.01), while the reduction in filling pressures during the head-up tilt was counteracted by PP. During PP with a head-up tilt, the filling pressures did not differ from those in the horizontal position without PP. CI showed a certain dependency on filling pressures. It is concluded that PP causes signs of elevated preload and afterload. The combination of PP and a head-up tilt is associated only with signs of an elevated afterload.(ABSTRACT TRUNCATED AT 250 WORDS)

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In cardiovascularly healthy patients, the left ventricular volume is increased during pneumoperitoneum. Further, changes in invasive pressure determinations (PCWP) do not correlate linearly with changes in volume indices of left ventricular filling (EDA).