[Peripheral circulatory effects of sodium nitroprussate. Evaluation by plethysmography and capillaroscopy]

Circulatory effects of intravenous injection of sodium nitroprusside are appreciated in 6 patients by monitoring systemic pressure, heart rate, digital systolic pressure, pulse plethysmography and nail-fold capillaroscopy. Low doses of nitroprusside (1.5 microg./kg/mn) enhance digital blood flow (+ 78.9%) and maximum height of the plethysmographic curve (+ 71.6%), without any significant modification of the systemic blood pressure (- 0.6%), heart rate (+ 6.3%) and digital pressure (- 1.15%). The peripheral resistances are strongly reduced. Nail fold capillaroscopy is unchanged. Higher doses, even with an adequate vascular filling, are potentially harmful for microcirculation.