Summary.We studied the effect of intravenous (i.v.) adminisration of 200 mg of iron sucrose following an i.v. bolus injection of recombinant human erythropoietin (r-HuEPO; 300 U/kg body weight) in seven subjects and compared it with seven subjects treated with r-HuEPO alone. Reticulocytes, serum erythropoietin (EPO) and ferritin levels were studied at baseline and daily for the following 8 d. Use of i.v. iron abolished the marked reduction in serum ferritin observed with r-HuEPO administration. Although the total number of reticulocytes was not affected by i.v. iron administration, the reticulocyte Hb content and retHb (a measure in g/l of the Hb contained in all reticulocytes) were increased in the i.v. iron/r-HuEPO group compared with the group who received r-HuEPO alone. Therefore i.v. iron significantly potentiates the haemopoietic response to r-HuEPO in normal subjects.

Assessment of the effect of clonidine on depth of anaesthesia is difficult because clonidine combines analgesic, sedative and direct haemodynamic effects. We thus evaluated the influence of clonidine on the bispectral index (BIS) and its potential dose-sparing effect on propofol. After induction of anaesthesia with target-controlled infusion of propofol and obtaining an unchanged bispectral index (pre-BIS), clonidine 4 microg kg(-1) or placebo was administered randomly to 50 patients in a double-blind manner. Subsequently, if there was a decrease in BIS we reduced the target concentration of propofol until pre-BIS was reached. The pre-BIS was maintained and a remifentanil infusion was added during surgery. The courses of the BIS, heart rate and blood pressure were recorded and the total amounts of intra-operative propofol and remifentanil were determined. Assessment of implicit memory during anaesthesia was performed with an auditory implicit memory test consisting of item sequences. Administration of clonidine resulted in a decrease in the BIS from 45 (SD 4) to 40 (6) (P<0.001), which allowed a reduction of propofol target concentration from 3.3 (0.6) to 2.7 (0.7) microg ml(-1) (P<0.001) and measured propofol concentration from 2.9 (0.6) to 2.5 (0.7) kg ml(-1) (P=0.009) in order to maintain the pre-BIS value. During subsequent surgery, propofol requirements were reduced by 20% (P=0.002) in the clonidine group and a similar amount of remifentanil was used in each group. The increase in anaesthetic depth given by clonidine can therefore be measured with bispectral EEG analysis and allows reduction of the propofol dose to achieve a specific depth of anaesthesia.

Combined digital SpO2/ PcCO2 ear sensors are very promising to allow for a fast and reliable monitoring of patient's oxygenation, hyper-/hypocapnia and ventilation with one single non-invasive probe. Optimal primary signal processing--amplification and digitalisation within the probe--allow for fast and reliable downstream signal processing algorithms. The resulting short SpO2 response times give the medical staff more time to take appropriate actions.

To compare two modalities of iron supplementation for the preoperative stimulation of erythropoiesis using recombinant human erythropoietin (rhEPO), 12 adults in normal hemoglobin and iron status due for elective surgery were randomized to rhEPO 200 U/kg body weight subcutaneously twice weekly combined with either iron sucrose 200 mg intravenously twice weekly or iron sulfate 160 mg/day orally, for 3 weeks preoperatively. Efficacy was measured by the increases over baseline in hemoglobin, reticulocyte count, and ferritin determined 3 days before surgery; preoperative reticulocyte count and ferritin were significantly higher with intravenous iron, whereas the only significant intragroup increases in hemoglobin between time points also occurred in this group. Intravenous iron significantly boosts the hematopoietic response to rhEPO and prevents iatrogenic iron depletion in otherwise healthy candidates for elective surgery.

SummaryRadial artery tonometry provides continuous measurement of non-invasive arterial pressure (CNAP) by a sensor positioned above the radial artery. An inflatable upper arm cuff enables intermittent oscillometric calibration. CNAP was compared with invasive radial artery pressure recordings from the opposite wrist in 22 high-risk surgical patients with an inter-arm oscillometric mean arterial pressure difference ഛ10 mm Hg.Oscillometric, tonometric and invasive digital pressure values, and invasive and CNAP waveforms were obtained by the same instrument (Colin BP-508). Correlation coefficients (r) of invasive vs oscillometric values (n : 481 pairs) were 0.83, 0.90 and 0.92, and mean absolute errors of oscillometry were 7.6, 4.7, and 2.6 mm Hg for systolic, diastolic and mean arterial pressures, respectively. Correlation was poor for systolic (r : 0.80), diastolic (r : 0.77) and mean (r : 0.84) invasive vs CNAP values (n : 1375). Compared with oscillometry, mean absolute errors of 15.2, 10.9 and 9.4 mm Hg for systolic, diastolic and mean CNAP, respectively, were significantly (P : 0.001) higher. Mean prediction errors of CNAP, compared with invasive values, were 95.8 (SD 14.2) mm Hg for systolic, ;7.2 (8.3) mm Hg for diastolic and ;3.9 (8.8) mm Hg for mean arterial pressure. Individual patient accuracy of CNAP was assessed as good (individual prediction error -5 (8) mm Hg and individual absolute error -10 mm Hg) in seven patients, as acceptable (-10 (12) and -15 mm Hg) in 11 patients, and as inadequate in four of 22 patients. Individual accuracy of oscillometry was good or acceptable in all 22 patients. The trend in CNAP changes (difference between consecutive measurements) was sufficiently accurate during induction of anaesthesia, as only 47 (7.6 %), 14 (2.3 %) and 27 (4.4 %) of 616 systolic, diastolic and mean CNAP values differed by more than 10 mm Hg of invasive pressure trends. We conclude that: intermittent oscillometry provides accurate arterial pressure monitoring; CNAP measurements offer a reliable trend indicator of pressure changes during induction of anaesthesia and may be considered an alternative to invasive pressure measurements, should arterial cannulation be difficult in an awake patient; and accuracy of absolute CNAP values is only moderate and unpredictable, thus radial artery tonometry should not replace invasive monitoring in high-risk patients during major surgical procedures. (Br.