Dynamic exercise increases the transcranial Doppler determined mean blood velocity in basal cerebral arteries corresponding to the cortical representation of the active limb(s) and independent of the concomitant rise in the mean arterial pressure. In 12 rowers we evaluated the middle cerebral artery blood velocity response to ergometer rowing when regulation of the cerebral perfusion is challenged by stroke synchronous fluctuation in arterial pressure. Rowing increased mean cerebral blood velocity (57 +/- 3 to 67 +/- 5 cm s-1; mean +/- SE) and mean arterial (86 +/- 6 to 97 +/- 6 mmHg) and central venous pressures (0 +/- 2 to 8 +/- 2 mmHg; P < 0.05). The force on the oar triggered an averaging procedure that demonstrated stroke synchronous sinusoidal oscillations in the cerebral velocity with a 12 +/- 2% amplitude upon the average exercise value. During the catch phase of the stroke, the mean velocity increased to a peak of 88 +/- 7 cm s-1 and it was in phase with the highest mean arterial pressure (125 +/- 14 mmHg), while the central venous pressure was highest after the stroke (20 +/- 3 mmHg). The results suggest that during rowing cerebral perfusion is influenced significantly by the rapid fluctuations in the perfusion pressure.

A segmental or a subtotal colectomy reduced bloating and pain and improved defecation patterns significantly. Although patient satisfaction was rather high, there are significant risks of postoperative complications and future operations. The operated patients had a significant increased CTT, faecal load and colon length, compared to non-operated patients.

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The frequency and likely aetiology of systemic arterial hypotension occurring either during or following operation, in patients receiving steroids was analysed retrospectively. Hypotension occurred during surgery in 29 of 250 operations. Although patients receiving steroids until shortly before operation appeared more likely to develop hypotension during operation the differences were eliminated when allowance was made for the severity of the disease. In almost half of the instances of hypotension during surgery there was no adequate explanation. Hypotension occurred after surgery on eight occasions; there was one case of acute adrenocortical insufficiency, six of various types of circulatory failure and in one the cause as uncertain.