The cuff ballotability method was used in 120 adult patients to confirm the correct depth of insertion of the endotracheal tube after tracheal intubation. The correct tube position was assumed when the cuff of the endotracheal tube could be felt to distend over the suprasternal notch when the pilot balloon was squeezed and the pilot balloon was felt to distend when pressure was applied over the suprasternal notch. Chest radiography was performed later to confirm the position of the endotracheal tube. In all patients the tip of the endotracheal tube was found to be in the desired position, i.e. 3–7 cm from the carina – the level of T3–T4 vertebrae. We concluded this technique to be a simple and reproducible way to confirm the correct depth of insertion of endotracheal tubes.

In order to compare interscalene brachial plexus block performed with ropivacaine or bupivacaine, 45 healthy, unpremedicated patients, undergoing elective shoulder surgery, were randomly allocated to receive interscalene brachial plexus anaesthesia with 20 mL of either ropivacaine 0.75% (n=15), ropivacaine 1% (n=15), or bupivacaine 0.5% (n=15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved later with bupivacaine 0.5% (28±15 min) than with ropivacaine 1% (10±5 min) (P=0.005) and ropivacaine 0.75% (15±8 min) (P=0.0005). No differences in success rate were observed between the three groups; however, seven patients receiving bupivacaine 0.5% required intra-operative analgesic supplementation (fentanyl 0.1 mg intravenous) compared with one patient receiving ropivacaine 0.75%, and two patients treated with ropivacaine 1% (P=0.02). The time from the block placement to first request for pain medication was similar in the three groups (10.7±2 h, 11±2.4 h, and 10.9±3.9 h after 0.75% and 1% ropivacaine or 0.5% bupivacaine, respectively). We conclude that interscalene brachial plexus block performed with 20 mL of either 0.75% or 1% ropivacaine allows for a prolonged post-operative pain relief, similar to that provided by bupivacaine 0.5%, with short onset time of surgical anaesthesia.

Summary

Background and objectives: The aim of our study was to investigate the antimicrobial effects of dexmedetomidine and etomidate-lipuro, and to compare these effects with those of midazolam and propofol on Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa, Acinetobacter baumannii and extended-spectrum beta-lactamase Escherichia coli ( E. coli ESBL). Methods: All hypnotic dilutions were exposed to micro-organisms for 0, 30, 60, 120 and 240 min at room temperature in vitro. The inoculums taken from diluted suspensions were re-inoculated on blood agar and incubated for 18–24 h at 35°C after which a count of the colonies was compared. Results: Midazolam reduced the viable cells of S. aureus at 30, 60, 120 and 240 min, and also completely inhibited the growth of E. coli, P. aeroginosa, A. baumannii and E. coli ESBL. Dexmedetomidine, etomidate-lipuro and propofol, however, did not inhibit any of the micro-organisms tested. Conclusion:In vitro, midazolam had an antimicrobial effect on E. coli, P. aeroginosa, A. baumannii and E. coli ESBL. Like propofol and dexmedetomidine, etomidate-lipuro had no antimicrobial effect on any of the micro-organisms tested.

Summary

Background and objective: This prospective, randomized and blinded study compared the performance of a new needle-through-needle (NTN) kit (Epistar®; Medimex, Germany) with the double-space technique for providing combined spinal epidural anaesthesia during Caesarean section.

Methods: Following local Ethics Committee approval and patient consent, 200 females were randomized to receive combined spinal epidural anaesthesia by the double-space (n = 100) or NTN (n = 100) technique. The frequency with which the intrathecal component could achieve a T5 block to touch for Caesarean section without the need for epidural augmentation or an alternative technique was determined. The time from start of procedure to achieving a block height to T5 was recorded. Pain and backache at insertion, and at 24 h follow-up were recorded using a visual analogue scale. To remove any bias due to posture, 50% of each group were further randomized to receive their block in the sitting or in the left lateral position. To evaluate improvement of performance over time the success in the first 100 study patients were compared to the success in the second 100.

Results: A successful block to T5 with the double-space and NTN techniques were 80 vs. 54, odds ratio 0.29. Failure to enter the intrathecal space once the epidural space had been located occurred in 29 patients in the NTN group. Time to readiness for surgery was 15 min (95% confidence interval (CI): 12.7–17.4) and 12.9 min (95% CI: 11.5–14.3) for the double-space and NTN techniques, respectively. The median (interquartile range) visual analogue scores for discomfort at insertion were 30 (12.5–51.5) and 32 (12.75–60) and for postoperative backache 0 (0–10) and 0 (0–10.75) in the double-space and NTN groups, respectively. The number of epidural augmentations was similar in both the groups and posture made no difference. There was a tendency to increased success in the second half of the study.

Conclusion: The double-space technique had a greater success rate than the NTN technique.

Summary

Background and objectives: Magnesium sulphate infusion during general anaesthesia reduces anaesthetic consumption and analgesic requirements. The aim of this study was to assess the effects of postoperative magnesium infusion on duration of block, sedation and analgesic consumption after spinal anaesthesia.

Methods: Fifty ASA I–II patients were included in the randomized double blind study. Spinal anaesthesia was performed at L3–4 or L4–5 interspace with 12.5 mg 0.5% heavy bupivacaine, using a 25 G Quincke needle. Patients received a 5 mg kg−1 bolus of magnesium sulphate followed by a 500 mg h−1 infusion or saline in the same volumes for 24 h. Time to first pain, analgesic request, return of motor function, visual analogue pain and sedation scores were evaluated every 4 h during the 24 h postoperative period. The t- and U-tests were used for statistical analyses. Data were expressed as mean ± SD, with P < 0.05 being considered significant.

Results: Vital signs were stable during spinal anaesthesia and postoperative period. When compared to the control group, time to analgesic need was increased and total analgesic consumption was reduced in the magnesium group (meperidine consumption 60.0 ± 73.1 mg control group, 31.8 ± 30.7 mg magnesium group, P = 0.02).

Conclusions: Magnesium sulphate infusion may be used as an adjunct for reducing analgesic consumption after spinal anaesthesia.

Survey results continue to reveal that postoperative pain is insufficiently managed throughout Europe and the rest of the world. However, the efficient use of existing resources, as well as the introduction of novel technologies, may aid in its improvement. Use of an acute pain service has the potential to improve pain management through specialized patient care and utilization of effective analgesic techniques. Multimodal analgesic techniques, which include adjuvant non-opioids and/or regional analgesic techniques, can provide effective analgesia and reduce the amount of systemic opioids (or obviate the need) for postoperative pain management. Patient-controlled analgesia modalities may also offer improvements to pain management, as in practice they provide pain relief superior to the intermittent administration of bolus doses of opioids. A novel patient-controlled analgesia modality that has been approved by the European Medicines Evaluation Agency (EMEA) for the treatment of acute, moderate-to-severe pain is the needle-free, pre-programmed fentanyl HCl iontophoretic transdermal system. This system was shown in a recent US clinical trial to be comparable in efficacy to a standard regimen of morphine intravenous patient-controlled analgesia. Adverse events associated with the use of the fentanyl iontophoretic transdermal system are generally similar to those experienced by patients using intravenous morphine patient-controlled analgesia. Considerations regarding the selection of patients for treatment with the fentanyl iontophoretic transdermal system are similar to those with other patient-controlled analgesia modalities; sufficient upper limb mobility and alertness are required to operate the system. Utilization of the fentanyl iontophoretic transdermal system, together with the guidance of an effective acute pain service, may lead to improvements in postoperative pain management.

Summary

Background and objective: Epidural blocks should provide good analgesia for the treatment of chronic low back pain without any motor block to allow active physiotherapy. Epidural ropivacaine is known to produce less motor block compared to bupivacaine at anaesthetic concentrations. This prospective, randomized double blind study compares the analgesic, motor block, and haemodynamic effects of single shot epidural injections of ropivacaine 0.2% 10 mL with bupivacaine 0.125% in outpatients suffering from chronic low back pain.

Methods: Forty patients were assigned to receive either ropivacaine 0.2% (n = 20) or bupivacaine 0.125% (n = 20) within a series of eight single shot epidural blocks.

Results: Thirty-six patients received either ropivacaine 0.2% (n = 18) or bupivacaine 0.125% (n = 18) within a series of eight single shot epidural blocks. Both groups showed no significant differences either in analgesia, or in motor blockade or haemodynamic changes. Thus ropivacaine 0.2% did not reduce the incidence of motor block (9.0% of patients with motor block Bromage scores 1, 2 or 3 in ropivacaine or bupivacaine). The combination of repeated epidural analgesia and physiotherapy reduced the median pain-scores (visual analogue scale, 0–10) from 7 (SD ± 1.6) at the beginning of the study to 4.1 (SD ± 1.7) at the end of the series.

Conclusions: Both bupivacaine 0.125% and ropivacaine 0.2% appear suitable for epidural administration to outpatients with chronic low back pain attending for epidural analgesia associated with physiotherapy (physical therapy).

Summary

Background and objective: Hitherto, neither desflurane nor sevoflurane, with similar physicochemical properties, have been compared with regard to their effects on the central nervous system. We compared the effects of desflurane and sevoflurane on electrical cortical activity and sensory transmission at two anaesthetic concentrations in patients undergoing hysterectomy.

Methods: The 1 and 2 MAC in nitrous oxide/oxygen (55%/45%) of desflurane or sevoflurane were administered while electroencephalographic power spectra and the somatosensory-evoked potentials were measured and correlated with cardiovascular effects.

Results: Both volatile agents induced a concentration-related increase of power in the slow delta-band and a concomitant decrease of power in the fast beta-domain. There was a close correlation with regard to the decrease in beta-power and heart rate (r2 = 0.988) and systolic blood pressure (r2 = 0.952) following both agents. Desflurane and sevoflurane had little effect on the early N20-peak, but affected the late N100-peak. There was a concentration-related increase in latency and a depression of amplitude height. Changes were not significantly different between both agents.

Conclusions: Both desflurane and sevoflurane possess a similar profile with regard to their hypnotic effects and a similar outline in depressing propagation within the sensory nervous system. Cortical nervous effects are mirrored closely in heart rate and systolic blood pressure.

Summary

Background and objective: Hypotension, especially in elderly and hypovolaemic patients, is frequently associated with intravenous midazolam administration. The mechanisms are not completely understood. This study was designed to investigate the mechanisms involved in the relaxing effect of midazolam on coronary arteries.

Methods: The substance was studied in isolated porcine coronary artery rings precontracted by either potassium chloride or prostaglandin F2α.

Results: Midazolam caused vasodilatation in a concentration-dependent manner. Relaxation was more pronounced in prostaglandin F2α precontracted segments than in those treated with potassium chloride (P < 0.001). Vasodilatation was unaffected by Nω-nitro-l-arginine, indomethacin and glibenclamide. Tetraethylammonium chloride, an inhibitor of the BKCa K+ channel (a high conductance Ca2+-sensitive K+ channel), dose dependently attenuated the vasodilating effect of midazolam (P < 0.01).

Conclusions: Hyperpolarization of the smooth muscle cell in the vessel wall, elicited by the activation the BKCa K+ channel, may contribute to the vasorelaxing effect of midazolam.

In a double-blind, randomized, controlled study, 61 patients who received a standardized anaesthetic for day case arthroscopic knee surgery were studied. Group T (n=31) received tramadol 1.5 mg kg−1, and group F (n=30) received fentanyl 1.5 μg kg−1 at the induction of anaesthesia. All patients also received 20 mL of intra-articular bupivacaine 0.5% at the end of surgery. Assessments were made of pain at rest and on movement, analgesic requirements and side-effects at hourly intervals up to 6 h and by means of a postal questionnaire at 24 h and 48 h post-operatively. Group F had higher pain scores than group T at 4 h only [VAS 3.3 (1.6–5.5) vs. 2.4 (1–4), P=0.039, respectively; median (interquartile range)]. There were no other significant differences between the groups in terms of pain scores, supplemental analgesic requirements or incidence of side-effects. We conclude that tramadol offers little benefit clinically compared with fentanyl when used at induction of anaesthesia for day case arthroscopic knee surgery. Further studies are indicated in patients with more severe pain to determine the role of tramadol in post-operative analgesia.

The choice of hypnotics and opioids for rapid-sequence induction, and the use of premedication, is influenced by the choice of the muscle relaxant. Anaesthetic agents have a major influence on the quality of intubation when rapid-sequence induction is achieved without a muscle relaxant. Premedication is important, along with a high dose of propofol (2.5 mg kg−1 or more) and a short-acting opioid such as alfentanil (30–40 μg kg−1) or remifentanil (up to 4 μg kg−1). It has also been demonstrated that i.v. lidocaine can improve intubating conditions. When a muscle relaxant is used, the choice of the anaesthetic agents depends on the onset of action of the relaxant. With a rapid-acting compound such as rocuronium at a dose of 0.6 mg kg−1, the hypnotic agents need to be supplemented with only a small dose of opioids, e.g. alfentanil 10–20 μg kg−1. When succinylcholine, rocuronium 1.0 mg kg−1 or rapacuronium 1.5 mg kg−1 are used, excellent intubating conditions may be obtained by relatively smaller doses of hypnotic agents even without opioids; however, haemodynamic and intraocular pressure changes are better controlled when small doses of opioids are administered.

Background and objective In recent studies, ultrasonic diagnostic imaging has proved useful in the screening of the trajectory of the epidural needle. With regard to possible side-effects of spinal and epidural anaesthesia caused by vessel injury, we aimed to evaluate the usability of Colour Doppler imaging for the depiction of interspinous vessels in prepuncture examination.

Methods Ultrasonic examination of the L¾ interspace area was performed in 20 volunteers. Using a 4-MHz and a 7-MHz probe with B-mode and Colour Doppler imaging, respectively, we compared four settings for the quality of vessel depiction in the puncture area. Overall resolution was evaluated according to the distinction of landmarks. Vascular structures were identified by pulsation (B-mode) or blood flow (Doppler).

Results Colour Doppler imaging of the L3/4 interspace was unachievable using the 7-MHz transducer. Vessel detection was possible in 50% of the B-mode images and in all of the 4-MHz Doppler images. Vessels were perceptible from a diameter of 0.5 mm. Veins were the predominantly visible structures. Overall vessel visibility was best using 4-MHz Colour Doppler.

Conclusions Prepuncture Doppler imaging can provide the epiduralist with information regarding the position of vessels in the needle trajectory. This might help to reduce complications in regional anaesthesia.

Summary

Background and objective: Positive end-expiratory pressure (PEEP) may affect hepato-splanchnic blood flow. We studied whether a PEEP of 10 mbar may negatively influence flow-dependent liver function (indocyanine green plasma disappearance rate, ICG-PDR) and splanchnic microcirculation as estimated by gastric mucosal PCO2 (PRCO2). Methods: In a randomized, controlled clinical study, we enrolled 28 patients after elective cardiac surgery using cardiopulmonary bypass. In 14 patients (13 male, 1 female; age 48–74, mean 63 ± 7 yr) we assessed ICG-PDR and PRCO2 on intensive care unit admission with PEEP 5 mbar, after 2 h with PEEP of 10 mbar and again after 2 h at PEEP 5 mbar. Inspiratory peak pressure was adjusted to maintain normocapnia. Fourteen other patients (8 male, 6 female; age 46–86, mean 68 ± 11 yr) in whom PEEP was 5 mbar throughout served as controls. All patients underwent haemodynamic monitoring by measurement of central venous pressure, left atrial pressure and cardiac index using pulmonary artery thermodilution. Results: While doses of vasoactive drugs and cardiac filling pressures did not change significantly, cardiac index slightly increased in both groups. ICG-PDR remained unchanged either within or between both groups (PEEP10 group: 24.0 ± 6.9, 22.0 ± 7.9 and 25.5 ± 7.7% min−1 vs. controls: 22.0 ± 7.5, 23.8 ± 8.4 and 21.4 ± 6.5% min−1) (P = 0.05). The difference between PRCO2 and end-tidal PCO2 (PCO2-gap) did not change significantly (PEEP10 group: 1.1 ± 0.9, 1.3 ± 0.7 and 1.3 ± 0.9 kPa vs. controls: 0.8 ± 0.5, 0.9 ± 0.5 and 0.9 ± 0.5 kPa). Conclusion: A PEEP of 10 mbar for 2 h does not compromise liver function and gastric mucosal perfusion in patients after cardiac surgery with maintained cardiac output.