Summary

Background and objective: Preoperative epoetin alfa administration decreases transfusion requirements and may reduce transfusion complications, such as postoperative infection due to immune suppression and thus hospitalization time. This study examined the impact of preoperative epoetin alfa administration on postoperative recovery and infection rate.

Methods: In an open randomized controlled multicentre trial in patients undergoing orthopaedic surgery, the effects of preoperative administration of epoetin alfa vs. routine care were compared in six countries. Haemoglobin (Hb) values, transfusions, time to ambulation, time to discharge, infections and safety were evaluated in patients with preoperative Hb concentrations 10–13g dL−1 (on-treatment population: epoetin n = 460; control n = 235), from study entry until 4–6 weeks after surgery. Outcome was also compared in patients with and without transfusion.

Results: Epoetin-treated patients had higher Hb values from the day of surgery until discharge (P < 0.001) and lower transfusion rates (12% vs. 46%; P < 0.001). Epoetin treatment delivered no significant effect on postoperative recovery (time to ambulation, time to discharge and infection rate). However, the time to ambulation (3.8 ± 4.0 vs. 3.1 ± 2.2 days; P < 0.001) and the time to discharge (12.9 ± 6.4 vs. 10.2 ± 5.0 days; P < 0.001) was longer in the transfused than in the non-transfused patients. Side-effects in both groups were comparable.

Conclusions: Epoetin alfa increases perioperative Hb concentration in mild-to-moderately anaemic patients and thus reduces transfusion requirements. Patients receiving blood transfusions require a longer hospitalization than non-transfused patients.

Summary

Background and objective: The exact change in circulating blood volume (BV) during general anaesthesia is still unknown because there is no standard method of evaluating BV. We evaluated the changes in BV by general anaesthesia using simple and easy estimation methods.

Methods: Fourteen patients scheduled for minor surgery under general anaesthesia were enrolled. Propofol and vecuronium bromide were used for the induction of anaesthesia, and anaesthesia was maintained with sevoflurane and nitrous oxide. Haematocrit (Hct), total protein concentration (TP), as well as colloid osmotic pressure (COP) measured using a colloid osmometer, were determined before anaesthesia, and 30, 60 and 90 min after the induction of general anaesthesia. BV was calculated using Allen's formula and the changes in Hct, TP and COP. The estimated BV was compared with directly measured BV using indocyanine green dilution method (BVICG).

Results: Hct, TP and COP significantly decreased after the induction of anaesthesia (Hct: 42.1–39.4%; TP: 7.3–6.9 g dL−1; COP: 23–19 mmHg). The calculated BV as well as BVICG significantly increased after induction of anaesthesia (calculated by COP: 4.13–5.03 L; BVICG: 4.54–5.56 L). The change rate in BV calculated by the change of COP was larger than other calculated BVs, and was approximated to the change rate in BVICG. After emergence from anaesthesia, all values tended to return to baseline.

Conclusions: General anaesthesia increases BV. The value of BV calculated from the change in COP was most changeable.

Summary

Background and objective: To evaluate orotracheal intubation conditions after 1 min.

Patients and methods: A prospective randomized study with 376 adult American Society of Anesthesiologists (ASA) Grade I–III patients. Each patient received propofol, fentanyl and either suxamethonium (1 mg kg−1) or rocuronium. The intubating dose of rocuronium (2 × ED95) was preceded 4 min earlier by saline, or a 0.1 × ED95 priming dose of rocuronium, atracurium, cis-atracurium, vecuronium or mivacurium. Intubating conditions were graded as excellent, good or poor with respect to laryngoscopy, vocal cord position and movement and reaction to intubation and/or cuff inflation.

Results: There were significant differences (P < 0.05) in laryngoscopy between suxamethonium and rocuronium primed with saline, atracurium or cis-atracurium. With respect to vocal cord position and movement during intubation, rocuronium without priming differed significantly from all other groups and for reaction to insertion of tracheal tube and/or cuff inflation. Rocuronium without priming differed significantly from all other groups except for rocuronium primed with itself. The mivacurium group showed more signs of pre-curarization than other groups (P < 0.05). There were significant differences between rocuronium alone and the other groups when final intubating conditions were compared.

Conclusions: Priming rocuronium with 0.1 × ED95 of vecuronium, rocuronium, atracurium or cis-atracurium is a safe technique and did not increase risk of pre-curarization in healthy patients.

Summary

Background and objective: Prospective longitudinal studies now indicate that cognitive dysfunction following coronary artery bypass surgery (CABG) is both common and persistent. This dysfunction is due in part to the inflammatory response and cerebral ischaemia–reperfusion, with nitric oxide (NO) as an important mediator of both. We hypothesized that a clinically significant association exists between plasma concentrations of nitrate/nitrite (NO3−/NO2−) and cognitive dysfunction after CABG.

Methods: Cognitive assessment was performed on 36 adult patients the day before CABG, on the fourth postoperative day and 3 months postoperatively. Patient spouses (n = 10) were also studied.

Results: A new cognitive deficit was present in 22/36 (62%) 4 days postoperatively and in 16/35 (49%) of patients, 3 months postoperatively. Patients who had cognitive dysfunction 3 months postoperatively were more likely to have cognitive dysfunction and increased plasma NO3−/NO2− concentrations compared to the non-deficit group preoperatively (22.6 (9.2) vs. 27.6 (8.4)) (P = 0.002). Plasma NOx (NO3− plus NO2−) concentrations were greater in patients with cognitive dysfunction 3 months postoperatively, 2 h (24.2 (6.3) vs. 19.1 (5.2)) (P = 0.002), and 12 h postoperatively (24.8 (7.6) vs. 18.8 (5.6)) (P = 0.001). There was, however, a time course similarity in NOx elevations for both deficit and non-deficit groups.

Conclusions: Perioperative plasma NOx concentrations do not serve as an effective biomarker of cognitive deficit after CABG.

Summary

Background and objective: Aprotinin administration may decrease the incidence of stroke associated with coronary artery bypass surgery by an unknown mechanism. Astrocytes exposed to hypoxia produce proinflammatory cytokines and upregulate intercellular adhesion molecule (ICAM)-1 on cerebral endothelium. This study investigated the effects of aprotinin on cerebral endothelial activation by hypoxic astrocytes in vitro.

Methods: Mouse astrocytes were exposed to hypoxia in an anaerobic chamber for 4 h followed by reoxygenation for 24 h. Astrocyte-conditioned medium (ACM) collected from mouse astrocytes subjected to hypoxia/reoxygenation (HR) or normoxia were applied to mouse cerebral endothelial cell (MCEC) cultures for 4 and 24 h in normoxia. Endothelial cells were preincubated for 1 h with aprotinin (1600 KIU mL−1) prior to exposure to ACM. Flow cytometry was used to estimate endothelial ICAM-1 expression. Interleukin (IL)-1β space concentrations in ACM were estimated with enzyme-linked immunosorbent assay (ELISA). Repeated comparisons were made using analysis of variance (ANOVA) and post hoc Tukey test as appropriate. P < 0.05 was considered significant. Data is presented as mean (standard deviation, SD).

Results: MCEC ICAM-1 expression was greater after 24 h exposure to HR-ACM compared to normoxic-ACM (mean channel flouresence (MCF) 107.5 (4.5) vs. 74.3 (4.5), respectively, P < 0.001). ICAM-1 expression was decreased by aprotinin preincubation compared to control (MCF 91.0 (1.1) vs. 107.5 (2.1), P = 0.006). Supernatant IL-1β concentrations in astrocytes exposed to HR were greater than those exposed to normoxia (7.1 (0.2) vs. 4.1 (0.2), P = 0.01).

Conclusions: This may be a neuroprotective mechanism associated with aprotinin administration.

Summary

Background and objective: The phosphodiesterase-III (PDE-III) inhibitor enoximone-induced marked contractures in skeletal muscle specimens of malignant hyperthermia (MH) susceptible (MHS) human beings and swine. Whether this is a substance specific effect of enoximone or caused by inhibition of PDE-III remained unclear. Therefore, the effects of the PDE-III inhibitor amrinone in porcine MH normal (MHN) and MHS skeletal muscles were investigated.

Methods: MH-trigger-free general anaesthesia was performed in eight MHS and eight MHN swine. The MH status of the swine was determined by detection of the Arg615–Cys point mutation on chromosome 6 indicating MH susceptibility. Skeletal muscle specimens were excised for the in vitro contracture tests with amrinone. Amrinone was added cumulatively every 5 min to muscle specimens in order to obtain organ bath concentrations between 20 and 400 μmol L−1. The in vitro effects of amrinone on muscle contractures and twitches were measured.

Results: Amrinone-induced contractures in all skeletal muscle preparations. MHS muscles developed contractures at significantly lower bath concentrations of amrinone than MHN muscles. Contractures of MHS compared to MHN muscles were significantly larger at bath concentrations of 80, 100, 150, 200 and 400 μmol L−1 amrinone. Muscle twitches remained unchanged up to and including 200 μmol L−1 amrinone.

Conclusions: Inhibition of PDE-III in general elicited higher contractures in MHS than in MHN muscles. Therefore, a contribution of PDE-III and the cyclic adenosine monophosphate (cAMP) system in the pathophysiology of MH must be suspected.

Summary

Background and objective: The objective of this study was to determine the influence of preoperative anxiety on the activity of plasma cholinesterase and heart rate (HR) variability.

Methods: A total of 50 subjects were studied, 25 male patients one day preoperatively and 25 male volunteers without surgical intervention as a control group. Blood samples were taken to determine plasma cholinesterase activity. HR variability was recorded for a period of 256 beat-to-beat intervals and analysed by frequency domain analysis into very low frequency (VLF: 0.02–0.04 Hz), low frequency (LF: 0.04–0.15 Hz) and high frequency (HF: 0.15–0.4 Hz). LF/HF ratio and total power over the 0.02–0.4 Hz range were calculated. Anxiety levels were assessed using the hospital anxiety and depression scale, the self-rating anxiety scale and a visual analogue scale.

Results: The patient group had significantly higher anxiety scores. Plasma cholinesterase activity was significantly higher in patients vs. controls (6646 vs. 5324 units L−1). Total power, LF and HF were significantly lower in the patients (1489 vs. 2581 ms2; 656 vs. 1186 ms2; 491 vs. 964 ms2, respectively).

Conclusions: Preoperative anxiety increases plasma cholinesterase activity and decreases HR variability.

Summary

Background and objective: To prevent neurological complications, low-flow antegrade cerebral perfusion (ACP) is used during repair of complex congenital heart defects. To overcome technical problems, continuous monitoring of cerebral blood flow and oxygenation is mandatory. The aim of the study was to evaluate the effect of different ACP flow rates on cerebral oxygen saturation obtained by near infrared spectroscopy.

Methods: Ten consecutive neonates undergoing Norwood stage I were included. In addition to near infrared spectroscopy (Invos 5100; Somanetics Corp., USA) on both hemispheres, mean arterial pressure and transcranial Doppler flow velocity were measured continuously and arterial and jugular venous oxygen saturation intermittently. Cerebral oxygen extraction ratio was calculated. Measurement points were obtained after starting bypass, during ACP with flow rates of 30, 20 and 10 mL kg−1 min−1 and immediately after ACP. ANOVA and Tukey–Kramer multiple comparison test were used for statistics.

Results: The near infrared spectroscopy signal could be obtained in all children at all measurement points, whereas transcranial Doppler failed in 1 neonate at a flow rate of 30 mL kg−1 min−1, in 3 neonates at 20 mL kg−1 min−1 and in 4 neonates at 10 mL kg−1 min−1. With the reduction of flow there was a significant decrease of cerebral oxygen saturation on both hemispheres (right: 78 ± 8 to 72 ± 9 and 66 ± 8, P < 0.001; left: 71 ± 7 to 65 ± 7 and 60 ± 7, P < 0.001), of jugular venous oxygen saturation (94 ± 6 to 89 ± 13 and 83 ± 15, P < 0.001) and a significant increase in oxygen extraction ratio (9.1 ± 8 to 14.8 ± 14 and 21 ± 16, P < 0.001) respectively, for 30, 20, 10 mL kg−1 min−1.

Conclusion: Near infrared spectroscopy reliably detects flow alterations during ACP with profound hypothermia.

Summary

Background and objective: Propofol is an intravenous (i.v.) anaesthetic agent that possesses many of the qualities of an ideal anaesthetic agent. The most significant side-effect associated with propofol is pain on injection. Despite optimal therapy, the incidence of pain on propofol injection remains a problem. This prospective, randomized, double blinded study evaluated the effect of three different treatment strategies in decreasing pain on propofol injection.

Methods: We studied 102 adult, ASA I–II patients, scheduled for elective surgical procedures. Combination of i.v. lidocaine and nitrous oxide (N2O) in oxygen (O2) inhalation pre-treatment was compared with either treatment alone in the prevention of pain on propofol injection. A standard propofol injection technique and scoring system, to measure the pain on injection was used.

Results: Demographic variables were similar between the groups. The incidence of no pain on propofol injection was similar in the lidocaine and N2O groups (63.6% vs. 57.5%) (95% confidence interval (CI): 0.17–0.29, P = 0.61). Combination therapy was associated with a greater incidence of no pain on injection (84% vs. 63.6%) (95% CI: 0.06–0.48, P = 0.04).

Conclusion: Combination of i.v. lidocaine and N2O in O2 inhalation pre-treatment is more effective than either treatment alone in decreasing pain on propofol injection.

Summary

Background and objective: Volatile anaesthetics inhibit nicotinic acetylcholine receptors at clinically relevant concentrations with higher affinity for the neuronal nicotinic receptor. The inhibitory effects of propofol on nicotinic receptors have only been documented at supraclinical concentrations. The aim of this study was to determine recovery properties and train-of-four (TOF) fade of mivacurium during sevoflurane and propofol anaesthesia, in order to examine any differences both in the enhancement of the neuromuscular block (postjunctional effects) and in TOF fade (prejunctional effects).

Methods: Twenty ASA I–II adult patients were randomly allocated to maintenance of anaesthesia with sevoflurane (end-tidal concentration 2%) or propofol. Neuromuscular block was assessed by acceleromyography and a single dose of mivacurium (0.15 mg kg−1) was administered (in the sevoflurane group after 30 min of exposure to sevoflurane). We measured time for recovery of the first twitch of the TOF (T1) from 25–75%, time from 25% recovery of T1 to achieving a TOF ratio (TOFR) of 0.8, TOFR at 50%, 75% and 90% recovery of T1, and height of T1 at TOFR of 0.7 and 0.9. Data were tested using t-test for independent samples.

Results: Recovery times (mean (95% confidence interval, CI)) of mivacurium in the sevoflurane group (T1 25–75%, 11.3 (8.1–14.5) min; T1 25%-TOFR0.8, 19.1 (15.7–22.5) min) were significantly longer (P < 0.05) than in the propofol group (T1 25–75%, 6.5 (5.2–7.7) min; T1 25%-TOFR0.8, 11.3 (7.8–10.3) min). No differences were found in the relations between TOFR and T1 or vice versa, between the groups.

Conclusions: Recovery times after a single dose of mivacurium were prolonged by sevoflurane compared with propofol but no differences in TOF fade were observed between the two anaesthetics.

Summary

Background and objective: Sore throat and hoarseness rank, besides pain and nausea, among the most frequent subjective complaints after tracheal intubation for general anaesthesia. Our intention was to determine the incidence of postoperative sore throat from a large sample of patients and thus to identify the most important associated factors.

Methods: We prospectively followed up 809 adult patients who underwent elective surgical interventions and examined their history, the applied anaesthetic techniques, perioperative course and the occurrence, intensity and duration of postoperative throat complaints. The assignment and professional experience of the involved intubators were also assessed. The influence of a multitude of variables on postoperative throat complaints was statistically analysed.

Results: Postoperative sore throat was present in 40% overall being significantly higher in female than in male (44% vs. 33%; P = 0.001). The mean pain intensity in the affected patients (n = 323) was 28 ± 12 mm on a visual analogue scale where 0 = no pain and 100 = extreme pain. The average duration was 16 ± 11 h. Main factors associated with throat complaints were female sex, history of smoking or lung disease, duration of anaesthesia, postoperative nausea, bloodstain on the endotracheal tube and natural teeth. We could find no influence on the occurrence or intensity of throat complaints by the professional assignment or the length of professional experience of the personnel involved.

Conclusions: Postoperative throat complaints frequently arise after tracheal intubation for general anaesthesia in the first 2 postoperative days, but they are of limited intensity and duration.