A device based on the laser Doppler perfusion meter, "Periflux", was constructed for continuous post-operative monitoring of the circulation of free flaps. It was evaluated in 17 consecutive clinical free flaps, four of which were beset by circulatory complications. In all 17 cases the device provided reliable and readily accessible information concerning the state of flap blood flow.

1 Twelve healthy subjects received 10 mg morphine HCI delivered transdermally from an occlusive reservoir applied to a small area of skin, painlessly de-epithelialised by vacuum suction. On a separate occasion, 10 mg morphine HCI was given as an i.v. infusion over 20 min. 2 Venous blood samples were collected serially for 72 h and assayed for morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by h.p.l.c. Pupil size, salivation, and central nervous effects ( nausea, fatigue, headache, feeling of heaviness and dysphoria/euphoria) were also measured. 3 After transdermal application morphine was absorbed by a first-order process to produce relatively constant plasma drug concentrations over 11 h. The absolute bioavailability of transdermal morphine was 75% (65-85%; 95% CI). The plasma concentrations of both M6G and M3G were lower after transdermal administration than after i.v. infusion, and a considerable delay (of up to 1 h) was observed before the metabolites were detectable. AUC ratios for M3G and M6G relative to morphine were similar after both modes of administration. 4 Non-analgesic effects were less pronounced at the lower plasma drug and metabolite concentrations observed after transdermal delivery than after the i.v. infusion of morphine. 5 Transdermal administration of morphine warrants investigation as an alternative route of morphine delivery.

Epithelialization and blood flow in painlessly inflicted small suction blister wounds were studied in healthy volunteers (n = 26) using evaporimetry and laser Doppler flowmetry (LDF), respectively. As expected, the evaporation rate normalized faster in wounds covered by an occlusive film than in wounds covered with gauze. The evaporimetry technique was found to be a simple alternative to the biopsy-based methods that have previously been used in humans. Blood flow was increased after 25 min of suctioning, and the hyperemia increased further after equalization to atmospheric pressure. This wound hyperemia (day 1) was more pronounced than that observed during heating of adjacent skin, and more pronounced at a pressure of 400 mm Hg below atmospheric pressure than at 200 mm Hg below. The hyperemic response lasted for some days and was similar on arm and foot. A mechanical LDF linear scanner was used to create a flow profile across the wound into the adjacent skin. Six months after inflicting the lesions there was no visible scar. The findings suggest that this blister wound model may be useful for studying epithelialization and microcirculatory events after trauma and during early wound healing in humans.

Although the transfer of free flaps is nowadays accomplished with an increasing degree of safety, thrombosis of the microvascular anastomoses is still a problem. In order to avoid delay in re-operating, various methods for objective blood flow monitoring have been tried, among them Laser Doppler Flowmetry (LDF). When one reviews the literature, it is apparent that opinions differ about whether or not LDF is a reliable technique for this purpose. To focus on the need to interpret continuous recordings, this paper reports our findings in six latissimus dorsi free flaps chosen from our series of LDF monitoring procedures. One uneventful flap, no. 1, had an immediate postoperative LDF value of 4.5 perfusion units (PU). LDF values improved during the recovery period and the graphic recording showed fluctuations due to normal physiological variations of the blood flow in the flap. Another uneventful flap, no. 4, showed the same pattern, though at an appreciably lower level, 2 PU, on average. Flap no. 2 had an acceptably high value of 3.5 PU despite suffering a venous thrombosis. However, the LDF recording showed no fluctuations and the value declined gradually. Another flap, no. 3, showed fluctuations and blood flow was normal although the value decreased to 2.5 PU. In flap no. 5, any value between 2 and 3.5 PU could be obtained merely by adjusting the position of the probe in the holder. In no. 6, the LDF value suddenly dropped, accompanied by a decrease in the total amount of backscattered light, indicating venous obstruction which was confirmed at re-operation.(ABSTRACT TRUNCATED AT 250 WORDS)

1 Twelve healthy subjects received 10 mg morphine HCI delivered transdermally from an occlusive reservoir applied to a small area of skin, painlessly de-epithelialised by vacuum suction. On a separate occasion, 10 mg morphine HCI was given as an i.v. infusion over 20 min. 2 Venous blood samples were collected serially for 72 h and assayed for morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by h.p.l.c. Pupil size, salivation, and central nervous effects ( nausea, fatigue, headache, feeling of heaviness and dysphoria/euphoria) were also measured. 3 After transdermal application morphine was absorbed by a first-order process to produce relatively constant plasma drug concentrations over 11 h. The absolute bioavailability of transdermal morphine was 75% (65-85%; 95% CI). The plasma concentrations of both M6G and M3G were lower after transdermal administration than after i.v. infusion, and a considerable delay (of up to 1 h) was observed before the metabolites were detectable. AUC ratios for M3G and M6G relative to morphine were similar after both modes of administration. 4 Non-analgesic effects were less pronounced at the lower plasma drug and metabolite concentrations observed after transdermal delivery than after the i.v. infusion of morphine. 5 Transdermal administration of morphine warrants investigation as an alternative route of morphine delivery.