This study investigated the neuroprotective effect of acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4, HES) on focal cerebral ischaemia-reperfusion injury and determined optimum degree for haemodilution in the rat.

Male Sprague-Dawley rats were randomly divided into three groups (n = 10 each): hydroxyethyl starch, saline and controls. Animals in the hydroxyethyl starch and saline groups were haemodiluted until haematocrit decreased to 30% of baseline. In another experiment male Sprague-Dawley rats were randomly assigned to four groups (n = 10 each): HES30, HES25 and HES20 and controls. Rats in the HES30, HES25 and HES20 groups were haemodiluted with hydroxyethyl starch until the haematocrit decreased to 30%, 25% and 20%, respectively. At 15 min after haemodilution, all the rats were subjected to a right middle cerebral artery occlusion for 120 min. Neurologic deficit scores and infarct volumes were assessed 24 h after reperfusion.

Haemodilution with hydroxyethyl starch improved neurologic outcome (P < 0.01) and reduced infarct volume (P < 0.01) compared to saline and controls. Haemodilution with saline augmented infarct volume (P < 0.05 vs. controls). Neurologic deficit scores in HES30 and HES25 groups were significantly lower compared to controls (P < 0.05) while infarct volumes in controls and HES20 were significantly larger compared to HES30 and HES25 (P < 0.01).

This study demonstrates that acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4) reduces infarct volume and improves neurological outcome after focal cerebral ischaemia in a rat stroke model. Neuroprotection by haemodilution was highest at haematocrit dilution between 25% and 30%, while ischaemic injury was exacerbates when haematocrit was diluted to 20%.

It has been demonstrated that volatile anaesthetics have cardioprotective properties during open-heart procedures, especially when administered continuously. European Council Directive 93/42/EEC concerning medical devices bans the supplementary incorporation of anaesthetic vaporizers in the bypass circuit. Since the uptake of volatile anaesthetics via diffusion membrane oxygenators is severely reduced, it is hypothesized that clinically relevant concentrations of sevoflurane will remain in the patients’ blood following saturation with a volatile agent before start of cardiopulmonary bypass. This study was designed to compare conventional and diffusion membrane oxygenators regarding their in vivo elimination of sevoflurane.

Twenty patients undergoing elective coronary bypass surgery were randomly allocated to two groups, either using a conventional polypropylene membrane oxygenator or a plasma-tight poly-(4-methyl-1-pentene) membrane oxygenator in a miniaturized extracorporeal circuit. Anaesthesia was maintained with sevoflurane, which was stopped at the start of cardiopulmonary bypass. During cardiopulmonary bypass, sevoflurane concentration was measured in blood and in the exhausted gas from the oxygenator.

The elimination of sevoflurane, expressed as the relative blood concentration, was significantly increased in polypropylene membrane oxygenators compared to poly-(4-methyl-1-pentene) membrane oxygenators. This resulted in an approximately threefold higher sevoflurane blood concentration in the poly-(4-methyl-1-pentene) group over the course of cardiopulmonary bypass.

With the incorporation of a poly-(4-methyl-1-pentene) oxygenator in a miniaturized bypass circuit, relevant concentrations of a previously applied volatile agent can be maintained even without further supply throughout cardiopulmonary bypass. This might be an alternative approach to cardioprotection when sevoflurane cannot be administered through cardiopulmonary bypass.

The alpha-2 adrenergic agonists clonidine and dexmedetomidine are used as an antihypertensive and a sedative, respectively. The aim of this study was to determine the effects of these agonists on ovalbumin-sensitized airway tone in guinea pigs.

The animals were divided into two groups: control and sensitized. The sensitized group received ovalbumin intraperitoneally and was boosted by exposure to aerosolized ovalbumin. The effects of the alpha-2 agonists were investigated by measuring (1) total lung resistance and (2) smooth muscle tension using a tracheal ring preparation.

In the control group, acetylcholine significantly increased total lung resistance in a dose-dependent manner. In the sensitized animals, total lung resistance was significantly higher (by 95%) at 6 μg kg−1 acetylcholine than that in the control group. Both clonidine and dexmedetomidine had a slight but significant inhibitory effect on the response curve of lung resistance at higher concentrations of carbachol, a potent muscarinic receptor agonist. Similar to the data obtained in the control group, both clonidine and dexmedetomidine significantly decreased total lung resistance and the inhibitory effects of these alpha-2 agonists on lung resistance were significantly distinguishable. Similar direct inhibitory effects of the alpha-2 agonists on carbachol-induced muscle contraction were observed in both the control and sensitized groups, the inhibitory effects in the sensitized group being significantly greater.

Both clonidine and dexmedetomidine can relax the airway even in the hyper-reactive state.

α2-Adrenoceptor agonists administered into the intrathecal and epidural space have been found to be effective in the treatment of chronic pain. Moreover, it was shown that they increase the analgesic effects of local anaesthetics and provide sedation, anxiolysis and haemodynamic stability. Dexmedetomidine, a potent and highly selective α2-adrenoceptor agonist, is in current clinical use, particularly in the intensive care unit. Our aim was to investigate whether dexmedetomidine produced motor and sensory blockade and neurotoxic effects when administrated via the epidural catheter in rabbits.

Twenty-one New Zealand white rabbits were included in the study. Animals were randomized into three groups. In Group L: lidocaine (2%), in Group LD: lidocaine (2%) + dexmedetomidine (5 μg) and in Group D: dexmedetomidine (10 μg) were administered by epidural catheter. Motor and sensory blockade were evaluated. After the evaluation of block, the animals were euthanized and their spinal cords removed for neuropathological evaluations.

Motor and sensory blockade were lower in Group D than in Group L and Group LD (P < 0.01). Although there were no differences between the groups for ischaemia of the medulla spinalis, evidence of demyelinization of the oligodendrocytes in the white matter in Group D was significantly higher than in Group L (P = 0.035).

We observed that dexmedetomidine does not have motor and sensory effects, but it may have a harmful effect on the myelin sheath when administered via the epidural route.

The elderly represent a wide and increasing patient population and significant numbers of elderly patients have chronic renal disease. This study aimed to investigate the neuromuscular effects of 0.6 mg kg−1 rocuronium under propofol anaesthesia in young adults and elderly patients with or without renal failure.

The neuromuscular effects of rocuronium 0.6 mg kg−1 under propofol anaesthesia were investigated in 40 patients with renal failure undergoing arteriovenous shunt surgery, of whom 20 were young adults (18–50 yr) and 20 were elderly (>65 yr) and in 40 patients with normal renal function undergoing peripheral venous surgery, of whom 20 were young adults and 20 were elderly. Neuromuscular transmission was monitored using acceleromyography. The times to recovery of the twitch (T1) to 25%, 50%, 75% and 90% and of the train-of-four ratio to 70%, and the recovery index were recorded.

The times to recovery of the first twitch to 25%, 50%, 75% and 90% and train-of-four to 70% and recovery index were found to be prolonged in both young and elderly patients with renal failure compared to those with normal renal function (e.g. T1 25%: 58.4 ± 20.2 and 80.1 ± 23.7 min vs. 32.8 ± 5.6 and 46.3 ± 9.0 min, respectively) (P < 0.05). These parameters were also prolonged in the elderly when compared with young adults in both the renal failure and the non-renal failure groups.

The neuromuscular effects of 0.6 mg kg−1 rocuronium under propofol anaesthesia were markedly prolonged in young and elderly renal failure patients compared to patients with normal renal function, and also in elderly patients with normal renal function compared with young adults.

Sevoflurane has been shown to distinctly reduce bronchial mucus transport velocity, an essential determinant of mucociliary clearance and pulmonary complications. However, sevoflurane is regarded as one of the least irritant volatile anaesthetics, especially when compared with desflurane. Hence, the aim of this double-blind, randomized, controlled trial was to assess differences in bronchial mucus transport velocity between sevoflurane and desflurane.

Twenty patients listed for general surgery were randomized to receive either maintenance of anaesthesia with desflurane and fentanyl, or sevoflurane and fentanyl. Thirty minutes after tracheal intubation, bronchial mucus transport velocity was assessed by fibreoptic observation of the movement of methylene blue dye applied to the dorsal surface of the right main bronchus.

Both agents distinctly reduced bronchial mucus transport velocity when compared with previous studies, but the degree of impairment did not significantly differ between the investigated groups (median [25%/75% percentile]): desflurane 1.5 [0.5/4.2] vs. sevoflurane 1.3 [0.3/2.9] mm min−1, P = 0.343).

Desflurane is commonly regarded as more irritant to the airway, but as far as bronchial mucus transport velocity is concerned, the choice between sevoflurane and desflurane does not seem to matter.

Postoperative acute renal failure predicts morbidity and mortality. We investigated the effect of nifedipine infusion on glomerular filtration rate in patients with impaired renal function undergoing cardiopulmonary bypass surgery.

Twenty patients accepted for coronary bypass and/or heart valve surgery were enrolled prospectively and randomized to nifedipine infusion or no treatment. Males and females with creatinine ⩾150 μmol L−1 and ⩾130 μmol L−1, respectively, were included. Patients with unstable angina pectoris, ejection fraction ⩽35% and those on dialysis were excluded. Glomerular filtration rate was measured preoperatively and 48 h postoperatively. Creatinine clearance was measured preoperatively and 0–4, 20–24 and 44–48 h postoperatively. There were no statistically significant differences in patient characteristics. Biochemical markers in plasma and urine were measured before and 48 h after surgery.

The mean ± SD preoperative glomerular filtration rates were 32.2 ± 11.5 and 31.4 ± 17.0 mL min−1 per 1.73 m2 in the nifedipine and control groups (P = 0.90), respectively. There was no statistically significant change in the glomerular filtration rate or in creatinine clearance over time within or between groups. A linear mixed model showed no effect of nifedipine (P = 0.44), time (P = 0.97) or interaction of nifedipine and time (P = 0.99) on creatinine clearance. Perioperative arterial pressure was kept within predefined targets. Three patients received dialysis postoperatively, all in the control group (P = 0.21). There were no statistically significant differences between groups in changes of urinary or plasma biochemistry.

Renal function was well preserved after cardiopulmonary bypass surgery in patients with impaired renal function when maintaining thorough intensive care surveillance. Nifedipine did not influence early postoperative renal function.

There have been many studies to find the optimum anaesthetics to provide excellent conditions for laryngeal mask insertion. We compared the effects of dexmedetomidine administered before propofol, on laryngeal mask insertion with fentanyl combined with propofol.

In all, 52 patients, ASA I–II, scheduled to have minor urological procedures were randomized into two groups. Group F received 1 μg kg−1 fentanyl (in 10 mL normal saline) and Group D received 1 μg kg−1 dexmedetomidine (in 10 mL normal saline). We used 1.5 mg kg−1 propofol for induction and 50% N2O and 1.5% sevoflurane in oxygen for maintenance. We observed jaw mobility (1: fully relaxed; 2: mild resistance; 3: tight but opens; 4: closed), coughing or movement (1: none; 2: one or two coughs; 3: three or more coughs; 4: bucking/movement) and other events such as spontaneous ventilation, breath holding, expiratory stridor and lacrimation. In each category, scores <2 were acceptable for laryngeal mask insertion.

More patients developed apnoea and their apnoea times were longer in Group F than Group D (P < 0.001). Respiratory rates increased in Group D (P < 0.001). Adverse events during laryngeal mask insertion were similar. The reductions in systolic and mean blood pressures were greater in Group F (systolic: P < 0.05, mean: P < 0.01). Emergence times were shorter in Group F than in Group D (P < 0.001).

Dexmedetomidine, when used before propofol induction provides successful laryngeal mask insertion comparable to fentanyl, while preserving respiratory functions more than fentanyl.

A single cardiac troponin I (cTnI) 24-h measurement is an independent predictor of short- and long-term adverse outcome after coronary surgery. We compared a single cTnI 24-h measurement and kinetic analysis of cTnI release in predicting in-hospital outcome in unselected cardiac surgery patients.

Consecutive patients (n = 184) undergoing cardiac surgery with cardiopulmonary bypass were included and divided into two groups according to the time course of postoperative peak serum cTnI (6 or 24 h after surgery). Serial measurements of cTnI were performed the day before surgery, at the end of surgery and 6, 24 and 120 h after surgery in all patients. The total amount of cTnI released (integrated area under the curve), postoperative major adverse cardiac events (ventricular arrhythmias, myocardial infarction and congestive heart failure) and in-hospital death were recorded. Data are expressed as median (95% CI).

In all, 152 (83%) patients had an early peak cTnI (6 h after surgery) and 32 (17%) patients had a late peak cTnI (24 h after surgery). The integrated area under the curve differed between both groups: 159 (142–178) vs. 321 (255–590), respectively, P < 0.001. Major adverse cardiac events and/or death (22 vs. 9%, P = 0.04) was greater in patients with a late peak cTnI. The integrated area under the curve and the peak value of cTnI were no more accurate than a single 24-h measurement in predicting the occurrence of major adverse cardiac events and/or death.

Kinetic analysis of cTnI release was no more accurate than a single 24-h measurement in predicting in-hospital poor outcome.

Despite evidence of their prognostic power for non-surgical patients, the value of perioperative natriuretic peptides and cardiac troponins as markers of cardiac events is incompletely defined. This study sought to examine whether perioperative N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) levels could be used for the prediction of in-hospital cardiac events in elderly patients undergoing elective coronary artery bypass grafting.

Ninety-eight elderly patients (>75 yr) undergoing elective coronary artery bypass grafting with cardiopulmonary bypass were enrolled and followed up for 12–15 months. NT-proBNP and cTnT levels were measured before induction of anaesthesia and 12, 24 and 48 h after surgery. To identify the best discriminatory level of NT-proBNP and cTnT receiver operating characteristics curves were analysed.

Thirty-four patients experienced 54 in-hospital cardiac events. Patients with complications had significantly higher NT-proBNP and cTnT levels than those without complications. Receiver operating characteristics curve analysis revealed cut-off levels of 2361 pg mL−1 and 0.66 μg mL−1 for NT-proBNP and cTnT (sensitivity, specificity, positive predictive value and negative predictive value of 84.3%, 89.4%, 78.9% and 92.4%, and 93.7%, 74.2%, 63.8% and 96.1%, respectively) at 24 h after surgery to be associated with in-hospital cardiac events. An elevation of both biomarkers above these threshold values was independently associated with individual postoperative complications (odds ratio, 18.9; 95%, CI, 2.3–106.1).

In elderly patients undergoing elective coronary artery bypass grafting surgery, high values of NT-proBNP and cTnT measured 24 h after the end of surgery were independently associated with in-hospital cardiac events.

Volatile anaesthetics have gained more popularity recently due to the potential for cardiac protection. Ultra-fast-track anaesthesia implies the immediate extubation after cardiac surgery. The purpose of this prospective randomized double-blind controlled study is to compare the cardioprotective effects of sevoflurane and isoflurane in off-pump cardiac bypass surgery.

Forty patients undergoing elective off-pump cardiac bypass surgery with high thoracic epidural analgesia and immediate extubation at the end of surgery were randomized into two groups. During surgery, anaesthesia was provided with either 1 minimum alvelolar anaesthetic concentration of sevoflurane or 1 minimum alvelolar anaesthetic concentration of isoflurane. Troponin-T, creatine kinase-MB, left ventricular wall motion anomalies, time to extubation, respiratory functions and haemodynamic parameters were compared between the two groups by analysis of variance.

All patients were successfully extubated in the operating theatre with minimal postoperative pain. Serial creatine kinase-MB and troponin-T concentrations were not significantly different between the two volatile agents. Haemodynamic stability throughout surgery and contractility was not different between groups. However, extubation time was significantly shorter with sevoflurane (10 ± 5 min) compared to isoflurane (18 ± 4 min).

This study indicates that during off-pump cardiac bypass surgery, sevoflurane and isoflurane provide the same ischaemic cardioprotective effects. There is no difference for heart contractility and haemodynamic values during and after off-pump cardiac bypass surgery between the two agents. Sevoflurane allows a more rapid recovery from anaesthesia, but this does not translate into better pulmonary function or haemodynamics. Both agents are similar in ultra–fast-track off-pump cardiac bypass surgery.

It has been reported that the left molar approach of laryngoscopy can make difficult intubation easier. The aim of this study was to investigate whether left molar approach to laryngoscopy provided a better laryngeal view in cases of unexpected difficult intubation.

Following the approval of local Ethics Committee and written informed consent from the patients, out of 1386 patients who underwent general anaesthesia for surgery, 20 patients who could be ventilated by face mask but could not be intubated with conventional midline approach on the first attempt were included in the study. Those 20 patients, who had Grade III-IV laryngeal views on laryngoscopy by conventional midline approach, were subjected to left molar laryngoscopy, and their laryngeal views were evaluated. The external laryngeal compression was routinely used to improve the laryngeal view. When endotracheal intubation failed by left molar laryngoscopy, we performed the conventional midline approach again. All data were recorded.

Of the 20 patients studied, 18 had a Grade III laryngeal view and two had a Grade IV laryngeal view. Eighteen of them had a better laryngeal view with left molar laryngoscopy. Eleven of the 20 patients underwent successful intubation with the left molar laryngoscopy, which provided a significantly better laryngeal view and success rate of tracheal intubation than did the conventional midline approach (P < 0.01 and P < 0.01, respectively).

Left molar laryngoscopy can make unexpected difficult intubation easier and should be attempted in cases of difficult intubation.

Our aim was to compare a continuous infusion of remifentanil with intermittent boluses of fentanyl as regards the perioperative hormonal stress response and inflammatory activation in coronary artery bypass graft patients under sevoflurane-based anaesthesia.

In all, 42 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to a fentanyl group (n = 21, total fentanyl dose 2.6 ± 0.3 mg), or a remifentanil group (n = 21, infusion rate 0.25 μg kg−1 min−1). Haemodynamics, plasma levels of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone, cortisol, complement activation (C3a, C5b-9), interleukin (IL)-6, IL-8 and tumour necrosis factor-α were measured at T1: baseline, T2: intubation, T3: sternotomy, T4: 30 min on cardiopulmonary bypass, T5: end of surgery and T6: 8 h postoperatively. Troponin T and creatine kinase-MB were measured postoperatively.

Patients in the remifentanil group were extubated significantly earlier than fentanyl patients (240 ± 182 min vs. 418 ± 212 min, P = 0.006). Stress hormones 30 min after start of cardiopulmonary bypass showed higher values in the fentanyl group compared to the remifentanil group (antidiuretic hormone (ADH): 39.94 ± 30.98 vs. 11.7 ± 22.8 pg mL−1, P = 0.002; adrenocorticotropic hormone: 111.5 ± 116.8 vs. 21.81 ± 24.71 pg mL−1, P = 0.01; cortisol 185 ± 86 vs. 131 ± 82 ng mL−1, P = 0.04). The interleukins were significantly higher at some perioperative time points in the fentanyl group compared to the remifentanil group (tumour necrosis factor: T5: 3.57 vs. 2.37; IL-6: T5: 4.62 vs. 3.73; and IL-8: T5: 4.43 vs. 2.65 and T6: 2.61 vs. 1.13). However, cardiopulmonary bypass times and aortic cross-clamp times were longer in the fentanyl group, which may to some extent account for the differences.

The perioperative endocrine stress response was attenuated in patients supplemented with continuous remifentanil infusion as compared to intermittent fentanyl.

There is increasing evidence of gender differences in the pharmacokinetics and pharmacodynamics of aminosteroid neuromuscular blocking agents. Compared to males, females are more susceptible, requiring approximately 30% less rocuronium to achieve the same degree of neuromuscular block. However, little information is available whether this difference is applicable to modern benzylisoquinolines (cisatracurium).

In all, 848 patients (423 males, 425 females) undergoing general surgery under total intravenous anaesthesia with muscle relaxation, tracheal intubation and mechanical ventilation were studied. Patients were randomized to receive a single bolus dose of cisatracurium (0.1 mg kg−1, 221 males and 199 females) or rocuronium (0.6 mg kg−1, 202 males and 226 females). The onset time for 95% depression of T1, clinical duration until 25% recovery and recovery index (T1 from 25% to 75%) were determined with an NMT electromyographic module of the Datex-Ohmeda S/5 Anaesthesia Monitor. The data for male and female groups were compared with appropriate statistical tests (unpaired t-test, Mann–Whitney rank sum test and Fisher’s exact test).

In both groups (cisatracurium and rocuronium), males were significantly taller (P < 0.001) and heavier (P < 0.001) than females, but the body mass index was comparable. For rocuronium, the onset time was shorter 91.7 ± 14.3 s vs. 108.0 ± 14.6 s (P < 0.001) and the clinical duration was increased in females 43.3 ± 7.8 min vs. 31.3 ± 5.5 min (P < 0.001). In the cisatracurium group, both onset times (248.9 ± 60.7 s for males vs. 253.4 ± 70.9 s for females) and clinical duration (42.6 ± 6.9 min for males vs. 43.1 ± 6.9 min for females) were similar. The recovery index was identical for males and females in both groups.

Females were more sensitive than males to a single bolus dose of rocuronium. Under the study conditions described, the onset time was shorter and the clinical duration was increased in female patients. This suggests that the routine dose of rocuronium should be reduced in females compared to males. On the contrary, we could demonstrate no gender differences in the onset time or clinical duration of cisatracurium.

This study aimed to investigate the effect of 0.25% levobupivacaine infiltration of the sternotomy wound and the mediastinal tube sites on postoperative pain, morphine consumption and side-effects in patients undergoing cardiac surgery.

After obtaining Ethics Committee approval and informed consent, 50 patients aged 18–65 yr, undergoing coronary artery bypass grafting, were included in this study. Anaesthesia was induced with 5 μg kg−1 fentanyl, 0.3 mg kg−1 etomidate, 1 mg kg−1 lidocaine, 0.1 mg kg−1 vecuronium and maintained with 1–2% sevoflurane, 50% oxygen in air and fentanyl. Patients were randomized into two groups before sternal wire placement: sternotomy and mediastinal tube sites were infiltrated with either 60 mL 0.25% levobupivacaine (infiltration group, n = 25) or 60 mL saline placebo (control group, n = 25). All patients received intravenous morphine patient-controlled analgesia (bolus dose: 2 mg, lock-out time: 15 min, 4 h limit: 20 mg) after extubation. Postoperative pain at rest and on coughing was assessed by a visual analogue scale (0–10). Pain scores, sedation scores (Ramsay scale), haemodynamic and respiratory parameters, arterial blood gases and morphine consumption were recorded.

The times to extubation and visual analogue scale scores were similar between groups. Morphine consumption at 24 h was significantly lower in the infiltration group compared with the control group (29.5 ± 5.1 vs. 42.8 ± 4.7 mg, respectively, P < 0.05). The sedation scores were found to be significantly higher in the control group when compared with the infiltration group at 1, 2 and 4 h after extubation (P < 0.05), whereas sedation scores after 4 h were similar between groups.

Infiltration of the median sternotomy incision and the mediastinal tube insertion sites with 0.25% levobupivacaine in addition to morphine patient-controlled analgesia was found to be effective in reducing postoperative morphine consumption when compared with morphine patient-controlled analgesia alone during the initial 24 h after cardiac surgery.

This study examined attitudes and views held by stakeholders regarding their experience of training in spinal anaesthesia. The aim was to identify key factors related to learning and teaching processes which were perceived to influence the acquisition of competence in spinal anaesthesia.

The study was carried out at a busy acute tertiary referral teaching hospital over a period of 1 yr. It applied a qualitative research approach in three phases, namely (i) completion of preliminary questionnaires, (ii) completion of focused questionnaires and (iii) focus group discussions.

Five factors were perceived to be critical ‘determinants of learning’: (i) the existence of a formal, structured training programme; (ii) time constraints/theatre efficiency; (iii) trainer–trainee interaction; (iv) patient safety/trainee/trainer stressors; and (v) visualization of the anatomy and procedure.

The study highlighted the need for a formal and structured training programme in spinal anaesthesia, through which many of the undesirable and discouraging factors (such as stress, adverse trainer–trainee interaction and time constraints) identified in the study could be minimized. Further studies are needed to validate the results in other hospital settings, as well as to define the relative importance of each of the proposed determinants and their interrelationships.

The aim of this open, non-controlled, multi-centre study was to evaluate the pharmacokinetics and safety of a 24–72 h continuous epidural ropivacaine infusion in children aged 1–9 yr.

After induction of general anaesthesia, 29 ASA I–II children, scheduled for major surgery in dermatomes below T10 had lumbar epidural catheters placed. A bolus of ropivacaine, 2 mg kg−1, was given over 4 min, followed immediately by an infusion of 2 mg mL−1 ropivacaine 0.4 mg kg−1 h−1 for the next 24–72 h.

Plasma concentrations of total ropivacaine (mean 0.83 and 1.06 mg L−1 at 16–31 and 59–72 h, respectively) and α1-acid-glucoprotein (mean 13 and 25 μmol L−1 at baseline and 59–72 h) increased over the course of the infusion. Plasma concentrations of unbound ropivacaine were stable throughout the epidural infusion (mean 0.021 range 0.011–0.068 and mean 0.016 range 0.009–0.023 mg L−1 at 16–31 and 59–72 h, respectively) and were well below threshold levels associated with central nervous system toxicity in adults (0.35 mg L−1). Apparent unbound clearance (mean 346, range 86–555 mL min−1 kg−1) showed no age-dependency. No signs of systemic toxicity or cardiovascular effects were observed. All patients received additional analgesics with morphine.

Following a 24–72 h epidural infusion of ropivacaine 0.4 mg kg−1 h−1 in 1–9-yr-old children, the plasma concentrations of unbound ropivacaine were stable over time with no age-dependency.

The purpose was to study the agreement between cardiac output measurements with electrical velocimetry vs. intermittent thermodilution before and after coronary artery bypass graft surgery.

Cardiac output was measured simultaneously with electrical velocimetry and intermittent thermodilution before and immediately after coronary artery bypass graft surgery, and in the intensive care unit. Measurements were performed in three different body positions. The results were analysed according to Bland and Altman.

The mean bias of all 150 paired measurements in 16 patients was 0.21 ± 0.78 L min−1, and the mean error was 40%. Before skin incision the mean bias was 0.04 ± 0.41 L min−1, and the mean error was 25%. After skin closure the mean bias was 0.57 ± 0.92 L min−1, and the mean error was 42%. In the intensive care unit the mean bias was 0.26 ± 0.68 L min−1, and the mean error was 32%.

The agreement between cardiac output measurements with electrical velocimetry and intermittent thermodilution was clinically acceptable only before skin incision in coronary artery bypass graft surgery. The mean error was unacceptably high immediately after skin closure and was at a borderline level in the intensive care unit. Thus, the overall accuracy of cardiac output measurements with the electrical velocimetry technique during coronary artery bypass graft surgery is not clinically unacceptable.