The effect of morphine and hyoscine on dye concentration curves in plasma volume determination

Abstract

When Evans blue is injected into the circulation of normal individuals a constant dye concentration is reached within 20 min. and this concentration is maintained for a further 40 min. Subsequently it diminishes at a rate of about 5 % per hour [Crooke & Morris, 1942]. In the course of investigations uponi the plasma volume in patients with shock, however, unaccountable alterations in the concentration of dye were sometimes found. A systematic examination of the factors which might be responsible for such anomalous dye concentration curves has therefore been made.At first the anomalous results were thought to be associated with shock, but this was disproved by a normal curve occurring in a patient with severe traumatic shock, and whose systolic blood 1 30-pressure was consistently below 60 mm.a Hg (Fig. 1 a). In contrast to this, a e moderately shocked patient with second 1 40-X and third degree burns of the hands and g l30-face, whose systolic blood pressure variedfrom 140 to 150mm. Hg, had an anomalous g 1 20-O curve (Fig. 1b).

Observations on plasma volume estimations with the dye T 1824

“…In three of the volunteers estimations of dye were made by both methods. Details are given with the figure, and, in contrast, a dye-disappearance curve taken from the paper by Bowler et al (1944) an injection of morphine, or papaverine and hyoscine, or morphine and atropine was given. At periods varying between 30 and 65 min.…”

“…* Since this paper went to press Dr Crooke has informed us that the doses of the separate injections of drugs referred to in the paper by Bowler et al (1944) were usually morphine sulphate 16-2 ma., hyoscine hydrobromide 0-65 mg., and atropine sulphate 0-65 mg. …”

“…1/4) and sometimes of 32 mg. of morphine, and some had received proprietary mixtures of papaverine and hyoscine. Bowler, Crooke & Morris (1944) have reported that if blood-volume determinations are made with the dye T 1824 after patients have received injections of morphine or hyoscine or both, considerable fluctuations in the concentration of dye are found in a series of samples drawn over a period of several hours after the injection of dye. To estimate the plasma volume from the dye content of plasma samples, one may use either the dye content of a single sample of plasma drawn several minutes after the injection of dye, at a time at which it is assumed that the dye is properly mixed with the plasma and there has been negligible loss of dye from the circulating plasma; or an attempt may be made to correct for loss of dye by estimating the dye contents of a series of samples drawn at varying times after the injection of dye, and extrapolating through these values to zero time.…”

General Anaesthesia in Shock

“…The plasma volume was determined a second time at the end of all major operations in order to measure the haemorrhage. Anomalous dye-concentration curves were obtained in 10 patients, due to the previous injection of morphine or hyoscine (Bowler, Crooke, and Morris, 1944), but 9 patients had good second dye-concentration curves. Two of these showed an increase of plasma volume, three no change, and four a fall, but the changes were probably within the error of the method.…”

“…In all cases the pulse and respiration rates and the blood pressure were recorded at about three-minute intervals. Determinations of plasma volume (Crooke and Morris, 1942;Morris, 1944) were made and the dye-concentration curves followed at about 30-minute intervals until the end of the operation. The haemoglobin (Rimington, 1942) was also determined at the same intervals.…”