SIVAUK Education Section

In experimental and clinical studies, volatile anaesthesia has proven to possess cardioprotective properties. However, no randomized controlled trials on the use of isoflurane during the entire cardiac surgical procedure are available. We therefore compared isoflurane–sufentanil vs propofol–sufentanil anaesthesia in patients undergoing coronary artery bypass grafting.

One hundred patients were randomly assigned to receive isoflurane–sufentanil (I) (n = 51) or propofol–sufentanil (P) (n = 49) anaesthesia, aimed at the same hypnotic depth. Postoperative concentrations of cardiac troponin I (cTnI) were followed for 72 h. Secondary outcome variables were length of stay (LOS) in the intensive care unit (ICU) and in hospital, and 30 day and 1 yr mortality and morbidity, defined as acute myocardial infarction, arrhythmias, and cardiac dysfunction. Groups were compared by an on-treatment analysis, using linear mixed models for repeated measures.

Eighty-four patients completed the protocol (I: 41 vs P: 43). Postoperative cTnI concentrations increased to a maximum of I: 2.72 ng ml^–1 (1.78–5.85) and P: 2.64 ng ml^–1 (1.67–4.83), but did not differ between groups (P=0.11). LOS in the ICU and in hospital was similar [ICU I: 18 (17.0–21.5) vs P: 19 (17.0–22.0) h; hospital I: 9 (6.5–8.0) vs P: 8 (6.0–9.0) days]. Cardiac morbidity and mortality in hospital and 30 days after surgery did not differ between groups. One year after surgery, two patients had died of non-cardiac causes. No between-group differences in cardiac morbidity were found.

In this study, the use of isoflurane–sufentanil in comparison with propofol–sufentanil anaesthesia does not afford additional reduction of postoperative cTnI levels.

Clinical trial registration information: NCT00356746 (http://www.clinicaltrials.gov/ct2/show/NCT00356746?term=NCT00356746&rank=1).

Epiaortic ultrasound scanning (EUS) is regarded as the reference standard for detecting atherosclerosis in the ascending aorta (AA). Combined with appropriate surgical modifications, EUS use can significantly reduce the incidence of postoperative stroke when detecting severe AA atherosclerosis. A recently introduced modification of conventional transoesophageal echocardiography (TOE), known as the A-View method, has proven capable of inspecting the distal AA. The objective of this study was to quantify the diagnostic accuracy of modified TOE in assessing atherosclerosis of the distal AA.

After approval by the institutional medical ethical committee and after obtaining written informed consent, 465 consecutive patients above 65 yr old, undergoing elective cardiac surgery with a median sternotomy, were included. The study followed a cross-sectional diagnostic design. All consecutive patients underwent modified TOE followed by EUS (reference standard) to assess the severity of distal AA atherosclerosis. We constructed contingency tables to compare the presence (and severity) of atherosclerosis, detected by the two techniques.

The positive predictive value of modified TOE for the detection of clinically significant atherosclerosis was 67%, and the negative predictive value was 97%. The sensitivity was 95% and the specificity was 79%. One patient suffered a pulmonary haemorrhage, although he recovered without further sequelae. We did not observe any clinical significant haemodynamic or ventilatory effects.

The high negative predictive value and sensitivity show that modified TOE yields adequate diagnostic accuracy for excluding clinically relevant aorta atherosclerosis without significant cardiopulmonary side-effects, provided that the A-View catheter is introduced carefully.

The endocannabinoid system (ECS) is an endogenous signalling system which includes the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and specific G-protein-coupled endocannabinoid receptors (CB1 and CB2). Recent studies have described important roles of the peripheral ECS in human atherosclerosis, cardiometabolic disorders, heart failure, and systemic inflammation. We sought to study changes in plasma endocannabinoid concentrations during cardiac surgery (CS) under general anaesthesia with isoflurane/sufentanil, and during cardiopulmonary bypass (CPB).

We studied 30 patients undergoing CS with CPB. All patients received midazolam and sufentanil for induction and isoflurane and sufentanil for maintenance of general anaesthesia. Blood samples were drawn before and after induction of general anaesthesia, after the beginning of surgery, during and after weaning from CPB, and after admission to intensive care unit (ICU) after surgery. Endocannabinoid measurements were performed by HPLC-tandem mass spectrometry.

Induction of general anaesthesia led to a significant decline in plasma AEA concentrations [from mean (sd) 0.39 (0.03) to 0.27 (0.03) ng ml^–1, P<0.01]. CPB induced a pronounced increase in 2-AG concentrations [from 112.5 (163.5) to 321.0 (120.4) ng ml^–1, P<0.01], whereas AEA concentrations remained persistently low until admission to the ICU. 2-AG concentrations returned to preoperative values after surgery.

General anaesthesia with isoflurane significantly reduces plasma AEA concentrations. This could be a consequence of stress reduction after loss of consciousness. The significant increase in 2-AG after initiation of CPB may be part of an inflammatory response. These findings suggest that anaesthesia and surgery have differential effects on the ECS which could have substantial clinical consequences.

Recent evidence suggests that neuraxial and regional anaesthesia may influence the progression of the underlying malignant disease after surgery.

This retrospective cohort study assessed whether neuraxial anaesthesia would affect the progression of cervical cancer in 132 consecutive patients who were treated with brachytherapy in a tertiary cancer centre in Australia.

Age, American Society of Anesthesiologists status, International Federation of Gynecologists and Obstetricians (FIGO) cancer staging, invasion into the uterus, tumour volume, and tumour cell types were not significantly different between patients who received neuraxial and general anaesthesia during their first brachytherapy treatment. The use of neuraxial anaesthesia during the first brachytherapy was not associated with a reduced risk of local or systemic recurrence [hazard ratio (HR) 0.95, 95% confidence interval (CI) 0.54–1.67; P=0.863], long-term mortality from tumour recurrence (HR 1.46, 95% CI 0.75–2.84; P=0.265), or all-cause mortality (HR 1.46, 95% CI 0.81–2.61; P=0.209), after adjusting for other prognostic factors. Tumour recurrence and long-term survival were only significantly associated with the tumour cell type, tumour volume, and FIGO tumour staging. Sensitivity analyses using proportions of all brachytherapy sessions performed under neuraxial anaesthesia also did not show any beneficial effects of neuraxial anaesthesia on tumour recurrence and long-term survival.

Using neuraxial anaesthesia during brachytherapy for patients with cervical cancer was not associated with a reduced risk of tumour recurrence and mortality when compared with general anaesthesia.

The surgical stress index (SSI) is a new monitoring tool for the assessment of nociception during general anaesthesia. It is calculated based on the heart beat interval and the pulse wave amplitude. Correlation of SSI with nociceptive stimuli and opioid effect-site concentrations has been demonstrated, but the influence of isolated modulation of heart rate (HR) on SSI is still unclear. The aim of this study was to evaluate the effect on SSI of atropine administration and cardiac pacing.

In 18 anaesthetized ASA III ICU patients, either repetitive cardiac pacemaker stimulation or administration of atropine (10 µg kg^–1) was performed, and the effect on SSI, arterial pressure, spectral entropy, and bispectral index was analysed.

Cardiac pacing at 100 beats min^–1 was followed by an increase in SSI from 26 [17–35 (10–41)] to 59 [53–72 (48–78)] {median [inter-quartile range (range)]} (P=0.0006), whereas other variables remained unaffected. Also, atropine administration increased SSI from 27 [20–34 (16–39)] to 58 [48–70 (41–81)] (P=0.007) without significant effect on other variables except HR. A recalibration of SSI during cardiac pacing leads to a significant decrease in SSI to 49 [40–52 (36–57)] (P=0.03), whereas recalibration after atropine administration had no effect.

SSI values measured in patients receiving atropine or in patients with pacemakers should be interpreted cautiously.

The objective of this study was to examine the effects of low-dose pregabalin on the analgesic efficacy, side-effects, and recovery profile in patients undergoing laparoscopic cholecystectomy.

One hundred and sixty-two patients aged 18–65 yr, of ASA physical status I–III, undergoing elective outpatient laparoscopic cholecystectomy were recruited and randomized in this prospective, placebo-controlled, double-blind study to receive one of the following study medications orally: pregabalin 50 mg, pregabalin 75 mg, or placebo, 1 h before surgery and then every 12 h after operation for a total of three doses. Postoperative numeric pain scores, analgesic consumption, recovery score (QoR-40), and side-effects (opioid-related symptom distress scale) were assessed in the early postoperative period (every 15 min during the first hour, at 90, 120 min, 6, and 12 h) and at days 1, 2, and 7. Data were analysed using an intention-to-treat method.

Compared with the placebo group, the pain scores were lower in the pregabalin 75 mg group in the first 90 min after surgery (P<0.05). Pregabalin 50 mg resulted in pain reduction at 30 and 45 min (P<0.05) relative to placebo. The analgesic consumption, side-effects, and recovery scores were similar among the three groups.

Perioperative administration of pregabalin 75 mg provided limited analgesic benefit in the postoperative period. An updated meta-analysis confirms this finding (see Supplementary material).

Remifentanil is associated with increased incidence of post-anaesthetic shivering (PAS). The aim of this study was to compare the effects of intraoperative high and low doses of remifentanil on PAS.

We investigated 50 consecutive patients, aged <60 yr, who underwent gynaecological laparotomy. Patients who underwent prolonged surgery (>4 h) were excluded from the study. Anaesthesia throughout surgery was maintained with i.v. propofol and remifentanil, and epidural ropivacaine, and no nitrous oxide was used. Fifty patients were randomly assigned to receive intraoperative remifentanil at 0.1 µg kg^–1 min^–1 (low-dose group, n=25) or 0.25 µg kg^–1 min^–1 (high-dose group, n=25) until the end of surgery. Intraoperative analgesia was achieved by a fixed infusion rate of remifentanil and titrated epidural ropivacaine. PAS was evaluated by nursing stuff over the first hour after surgery.

PAS occurred more frequently in the high-dose group than in the low-dose group (60% vs 20%, P=0.009). None of the patients complained of pain during the observation period due to epidural analgesia. There were no significant differences in rectal or palm skin temperature after extubation between the two dose groups.

Remifentanil-induced PAS is not a phenomenon of intraoperative hypothermia. The higher incidence of PAS with higher doses of remifentanil probably reflects acute opioid tolerance and stimulation of N-methyl-d-aspartate receptors, similar to hyperalgesia. We conclude that patients administered high doses of remifentanil are sensitive to shivering after sudden drug withdrawal.

The patient state index (PSI) and the bispectral index (BIS) quantify anaesthetic depth based on the EEG using different algorithms. We compared both indices with regard to the prediction of the depth of propofol anaesthesia.

In 17 patients, propofol was infused until burst suppression occurred and stopped thereafter until BIS recovered to values above 60. This was repeated; afterwards, patients were intubated, for subsequent surgery. Without surgical stimulus, PSI and BIS were measured simultaneously and compared with the estimated effect-site concentrations of propofol. These were derived from simultaneous pharmacokinetic and -dynamic modelling in an individual two-stage and a population-based NONMEM approach.

A close sigmoid relationship was observed between the propofol effect-site concentration and both PSI [coefficient of determination ²=0.91 (sd 0.05)] and BIS [²=0.92 (0.03)], which was significantly steeper for PSI [=2.2 (0.6)] than for BIS [=1.8 (0.4)], and reached significantly lower values for PSI [E_max=0.3 (1.1)] than for BIS [E_max=5.3 (6.7)] at maximal propofol concentrations. A significantly smaller k_e0 was obtained for PSI [0.09 (0.03) min^–1] compared with BIS [0.10 (0.02) min^–1]. PSI and BIS correlated significantly with each other (²=0.866) and predicted propofol effect-site concentration with a comparable probability [P_K=0.87 (0.05) and 0.86 (0.05), respectively]. NONMEM revealed E₀=89.3 and 92.3, E_max=1.9 and 8.6, C_e50=1.38 and 1.92 µg ml^–1, =1.6 and 1.48, and k_e0=0.103 and 0.131 min^–1 as typical values for PSI and BIS, respectively.

The PSI and the BIS monitors performed equally well in predicting depth of propofol anaesthesia. However, PSI was lower than BIS by ~10–15 points at high propofol concentrations.

The primary goal of this study was to compare the size and depth of the internal jugular vein (IJV) and the subclavian vein (SCV) in infants under general anaesthesia. A secondary goal was to determine the correlation of weight, height, head circumference, and age to the size and depth of these veins.

Sixty small infants weighing from 1.4 to 4.5 kg were included. Using ultrasound, the diameters via short-axis (SAX) and long-axis (LAX) views, cross-sectional area (CSA), and depth of the left and right IJV and SCV were measured.

The diameter of the IJV was 7.9% larger on average than that of the SCV as measured via the SAX and LAX views (mean: 3.1 vs 2.9 mm; Wilcoxon's signed-rank test: P<0.01). The CSA of the IJV was 27% larger on average than that of the SCV (mean: 10.2 vs 8.0 mm²; Wilcoxon's signed-rank test: P<0.01). Seventy-five per cent of the neonates showed a larger CSA of the IJV. The SCV was 8.4% deeper on average from the skin surface than the IJV (mean: 6.4 vs 5.9 mm; Wilcoxon's signed-rank test: P<0.01). There was a significant positive correlation between weight, height, head circumference, and age to the size and depth of the veins (Spearman's rank correlation: P<0.01).

Because of its most likely larger size, the IJV can be recommended as the better choice for cannulation in comparison with the SCV. However, other factors should also be considered.

Capacity to ambulate represents an important milestone in the recovery process after total knee arthroplasty (TKA). The purpose of this study was to determine the analgesic effect of two analgesic techniques and their impact on functional walking capacity as a measure of surgical recovery.

Forty ASA II–III subjects undergoing TKA were enrolled in a randomized, double-blind, single-centre study receiving 48 h postoperative analgesia with either periarticular infiltration of local anaesthetic (Group I) or continuous femoral nerve block (Group F). Breakthrough pain relief was achieved with patient-controlled analgesia (PCA) morphine. The main outcome was postoperative morphine consumption. Early (postoperative days 1–3) and late (6 weeks) functional walking capacity (2 and 6 min walk tests, 2MWT and 6MWT, respectively), degree of physical activity (CHAMPS), health-related quality of life (SF-12), and clinical indicators of knee function (WOMAC, Knee Society evaluation, and range of motion) were measured.

Patients in Group F used the PCA less (P=0.02) to achieve adequate analgesia. Postoperative 2MWT was similar in both groups (P=0.27). Six weeks after surgery, recovery of 6MWT, physical activity, and knee function were significantly improved in Group F (P<0.05). Preoperative walking capacity, physical activity and early total walking time were the independent predictors of early recovery. Distance and time spent walking were the predictors of functional walking exercise capacity at 6 weeks after surgery.

Femoral block is associated with lower opioid consumption and a better recovery at 6 weeks than periarticular infiltration. Early postoperative activity measures (2MWT and walking time) were proved to be possible indicators of knee function recovery at 6 weeks after surgery.

Thoracotomy results in severe postoperative pain potentially leading to chronic pain. We investigated the potential benefits of oral celecoxib on postoperative analgesia combined with thoracic epidural analgesia (TEA).

Forty patients undergoing thoracotomy were included in this prospective, randomized, double-blind, placebo-controlled study. General anaesthesia was standardized. Patient-controlled epidural analgesia (T4–T5) was used during 48 h after surgery (ropivacaine 2 mg ml^–1 with sufentanil 0.5 µg ml^–1). Patients were allocated to receive oral celecoxib or placebo from the evening before surgery until 48 h after operation. Postoperative pain scores, respiratory function, and morbidity were compared between the two groups.

Postoperative pain scores at rest (P=0.026) and during coughing (P=0.021) were lower and patient satisfaction was greater (P=0.0033) in the celecoxib group. Consumption of the local anaesthetic solution was comparable between groups. Postoperative restrictive pulmonary syndrome and morbidity were comparable between groups.

Celecoxib improves postoperative analgesia provided by TEA after thoracotomy.

Choline is a dietary supplement that activates 7 nicotinic receptors. 7 nicotinic activation reduces cytokine production by macrophages and has antinociceptive activity in inflammatory pain models. We hypothesized that systemic administration of choline would reduce the inflammatory response from macrophages and have antinociceptive efficacy in a murine model of postoperative pain.

We studied the response of wild-type and 7 nicotinic knockout mice to heat and punctate pressure after a model surgical procedure. We investigated the effect of genotype and choline treatment on -bungarotoxin binding to, and their production of tumour necrosis factor (TNF) from, macrophages.

Choline provided moderate antinociception. The ED₅₀ for choline inhibition of heat-induced allodynia was 1.7 mg kg^–1 h^–1. The ED₅₀ for punctate pressure threshold was 4.7 mg kg^–1 h^–1 choline. 7 nicotinic knockout mice had no change in hypersensitivity to heat or pressure and were significantly different from littermate controls when treated with choline 5 mg kg^–1 h^–1 (P<0.05, 0.01). Choline 100 mM reduced binding of -bungarotoxin to macrophages by 72% and decreased their release of TNF by up to 51 (sd 11)%. There was no difference by genotype in the inhibition of TNF release by choline.

Systemic choline is a moderately effective analgesic via activation of 7 nicotinic acetylcholine receptors. The antinocicepive effect may not be mediated by a reduction of TNF pathway cytokine release from macrophages. Although choline at millimolar concentrations clearly inhibits the release of TNF, this effect is not 7 subunit-dependent and occurs at concentrations likely higher than reached systemically in vivo.

The peripheral deafferentation induced by regional anaesthesia (RA) results in misperception of size-shape (S) and posture (P) of the anesthetized limb. During RA, most patients seem to describe motionless ‘phantom limbs’ fixed in stereotyped illusory positions, suggesting that RA could unmask stable postural patterns. The question of whether movement illusions exist or not after anaesthesia needs a prospective study. This study aimed to describe the phenomenology of RA-induced kinesthetic illusions (K illusions).

We examined prospectively the body image alteration during infraclavicular blocks in 20 patients. Multimodal sensory testing (pinprick, heat-cold, pallesthesia, and arthrokinesia) and assessment of motor function were performed every 5 min for 60 min after administration of the local anaesthetics. Meanwhile, patients described phantom limb sensations (S, P, and K illusions).

We individualized the occurrence of K illusions [44 (8) min] with respect to S illusions [7 (3) min; P<0.005] and P illusions [22 (4) min; P<0.001]. A close relationship between the onset of K illusions and proprioceptive impairment (arthrokinesia: r=0.92, P<0.001; pallesthesia: r=0.89, P<0001) and abolishment of motor activity (r=0.83, P<0.001) was identified. Finally, a principal component analysis showed that S and P illusions were essentially related to the proprioceptive impairment.

This study analyses for the first time the temporal evolution of sensorimotor dysfunction and the onset of K illusions during RA. Our results suggest the involvement of an alteration of proprioception and motor functions in the origin of this phenomenon. These data agree with the motor awareness theory.

Neuraxial anaesthesia improves tissue perfusion and tissue oxygen tension. Vasodilation induced by this technique may result in hypotension requiring the administration of vasoactive drugs. The use of peripheral vasoconstrictors might counteract the improved tissue perfusion and its potentially beneficial effects. We therefore investigated the effect of i.v. norepinephrine and ephedrine on skin perfusion using laser-Doppler flowmetry (LDF) in patients during spinal anaesthesia.

Skin blood flow expressed in perfusion units (PU) provided by LDF was measured simultaneously at the foot and the manubrium levels in 44 patients during spinal anaesthesia with a sensory level below T5. Norepinephrine infusion was then titrated to normalize mean arterial pressure (MAP) in 23 patients (Group NOR). Ephedrine (max. 10 mg) was administered in 21 patients (Group EPH). Changes in relative PU were compared between the two sites of measurements in each group during drug administration. The same doses of norepinephrine were assessed in 11 normal volunteers to assure comparable vasoreactivity at the foot and manubrium levels.

Spinal anaesthesia resulted in a 10% decrease in MAP (P<0.001), an increase in relative PU values at the foot level (P<0.001), and a decrease at the sternum level (P<0.05). Norepinephrine and ephedrine produced a significant increase in relative PU values at the foot level when compared with the sternum level (NOR: P=0.02; EPH: P=0.0035). In volunteers, norepinephrine decreased cutaneous perfusion similarly at the manubrium and foot levels.

Improved skin perfusion induced by spinal anaesthesia was not counteracted by the use of norepinephrine or ephedrine.

The Cormack–Lehane (CL) classification is broadly used to describe laryngeal view during direct laryngoscopy. This classification, however, has been validated by only a few studies reporting inconclusive data concerning its reliability. This discrepancy between widespread use and limited evidence prompted us to investigate the knowledge about the classification among anaesthesiologists and its intra- and inter-observer reliability.

One hundred and twenty interviews were performed at a major European anaesthesia congress. Participants were interviewed about their general knowledge on grading systems to classify laryngeal view during laryngoscopy and were subsequently asked to define the grades of the CL classification. Inter- and intra-observer reliabilities were tested in 20 anaesthesiologists well familiar with the CL classification, who performed 100 laryngoscopies in a full-scale patient simulator.

Although 89% of interviewed subjects claimed to know a classification to describe laryngeal view during laryngoscopy, 53% were able to name a classification. When specifically asked about the CL classification, 74% of the interviewed subjects stated to know this classification, whereas 25% could define all four grades correctly. In the simulator-based part of the study, inter-observer reliability was fair with a coefficient of 0.35 and intra-observer reliability was poor with a of 0.15.

The CL classification is poorly known in detail among anaesthesiologists and reproducibility even in subjects well familiar with this classification is limited.

The LMA-Supreme^TM (SLMA) is a single-use, latex-free, supraglottic airway device with a drain tube which allows immediate assessment of correct positioning of the device at insertion and throughout the procedure and provides access to gastric contents. The anatomically shaped airway tube facilitates easy insertion in anaesthetized patients in the supine, lateral, and prone positions. We present a prospective audit in 205 consecutive adult patients presenting for elective spine surgery in the prone position. Patients positioned themselves in the prone position, on a Montreal or Wilson mattress to optimize patient comfort in this position. Anaesthesia was then induced, and an appropriate-sized SLMA was inserted.

Prospective, descriptive audit of SLMA insertion in 205 consecutive adult patients, anaesthetized in the prone position for elective orthopaedic surgery with spontaneous (n=6) or positive pressure ventilation (PPV) (n=199).

First-pass success was achieved in 184 insertions. Forty-two SLMA insertions were performed by anaesthesia trainees with first-pass success achieved in 38 insertions. All problems encountered during insertion were minor, and no patient had to be turned to the supine position for an airway problem. Problems during insertion were independent of patients' BMI. There were no failures of SLMA insertion or of maintenance of PPV during surgery.

The results suggest that the SLMA is a useful device for airway management in patients anaesthetized in the prone position and for subsequent airway management with PPV, with or without neuromuscular block.