Summary

Although local anaesthesia is mentioned in historical manuscripts, it is only a hundred years since Bier first reported the intrathecal use of local anaesthetic agents. This has been followed by a rapid progression in the art and science of spinal anaesthesia. Isomerically pure agents with favorable clinical profiles, such as ropivacaine and levobupivacaine are now available. Spinal anaesthesia is commonly used in a variety of situations, including orthopaedic, abdominal, gynaecological surgery, Caesarean section and the relief of pain in childbirth. Hyperbaric solutions of local anaesthetics appear to produce more consistent results than plain solutions and the addition of other drugs, such as opioids and clonidine may improve analgesia. In addition to traditional spinal anaesthesia, local anaesthetics are now being evaluated in continuous spinal anaesthesia and combined epidural–spinal anaesthesia. This article reviews clinical experience with levobupivacaine and ropivacaine. Compared with levobupivacaine, ropivacaine generally produces a less intense motor block of shorter duration, which has advantages for earlier mobilization and discharge from hospital and may be particularly useful in obstetrics and ambulatory surgery.

Summary

Background and objective: The development of acute renal failure (ARF) in critically ill patients is associated with an increase in hospital mortality. Recently, it was shown that starting renal replacement therapy early and using high-filtrate flow rates can improve the outcome, but this could not be confirmed in later investigations. Studying selected patient subgroups could provide a useful basis for patient selection in future trials evaluating the outcome of renal replacement therapies. We, therefore, investigated the impact of the underlying disease on the outcome of patients with ARF.

Methods: We retrospectively analysed 306 patients with ARF who were treated with renal replacement therapy. Patients were classified according to six initial diagnosis groups: haemorrhagic shock, post-cardiac surgery, post-liver transplantation, trauma, severe sepsis and miscellaneous. Univariate and multivariate multiple logistic regression analysis was used to determine which factors influenced the outcome.

Results: Underlying disease proved to be the only independent risk factor for mortality that was present at intensive care unit (ICU) admission (P = 0.047). Patients with severe sepsis had a significantly higher mortality rate (68%) than ARF patients as a whole (51%) (P = 0.02). Length of stay in the ICU, the use of catecholamines, the delay before ARF onset, and the correlation between APACHE II score and ICU length of stay proved to be additional independent predictors of outcome.

Conclusions: Patient selection and subgroup definition according to the underlying disease could augment the usefulness of future trials evaluating the outcome of ARF.

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 objective: Continuous spinal analgesia (CSA) offers considerable pain relief, and has been used in various procedures such as for surgery and cancer pain control. In Japan, portable and disposable infusion kits are increasingly employed for continuous epidural analgesia and CSA. In CSA, the use of a microcatheter is expected to reduce the incidence of spinal headache previously encountered with larger catheters. However, the flow rate of disposable infusion kits is reduced when used in conjunction with a microcatheter.

Methods: This study aimed to investigate the influence of catheter length on the flow rate of two different devices: 20- or 91-cm 28-G microcatheters connected to balloon- or syringe-type infusion pumps were examined (50 mL, 1 mL h−1). There were four groups each of 10 experiments: Group A: balloon-type infuser, 91 cm catheter; Group B: balloon-type infuser, 20 cm catheter; Group C: syringe-type infuser, 91 cm catheter; Group D: syringe-type infuser, 20 cm catheter.

Results: The mean flow rate in Group A was significantly less than that in Group B and the mean flow rate in Group C was significantly less than Group D (P < 0.05).

Conclusion: These results indicated that the use of a shorter microcatheter achieves a better flow rate during CSA.

Summary

Background and objective: Difficult intubation in obstetric units has been identified as a major contributory factor to anaesthesia related maternal morbidity and mortality. Availability of equipment for management of a difficult airway is associated with reduced maternal complications. The purpose of our survey was to describe the availability of difficult airway equipment in Irish Obstetric Units.

Methods: A telephone survey was conducted in which all respondents were asked whether they housed basic airway equipment, alternative ventilation and alternative intubation equipment within or close to their obstetric unit.

Results: The most important finding of this study is that all the obstetric units in Ireland hold at least one alternative device for both ventilation and intubation. The most common alternative ventilation device was the laryngeal mask airway and the most common alternative intubating device was the surgical airway device.

Conclusions: Irish Obstetric Units are well equipped according to the international guidelines for difficult intubation equipment. However, we believe that this situation could be further improved by training inexperienced anaesthetists in the use of the Intubating Laryngeal Mask and by the increased use of portable trolleys.

Summary

Background and objective: Epidural analgesia is widely used for abdominal surgery due to the properties of ‘stress-free’ anaesthesia and superior pain control. Nevertheless, sympathomimetics are known to antagonize inflammation. The present study was performed to investigate if epidural local anaesthetics caused increased local oedema formation.

Methods: Thirty Dansk Landrace pigs were randomized into three groups: epidural bupivacaine, epidural morphine or intravenous (i.v.) fentanyl. All animals were anaesthetized with isoflurane and i.v. midazolam and received an identical fluid regimen. Six small bowel resections were performed over a 3-h period and during the following 3 h the anastomoses were resected. Primary end-points were water content in small bowel and mesentery samples before and after gut anastomosis, lymph flow and urine production.

Results: The water content in the small bowel samples was not changed by surgery or by the different anaesthetic protocols. In the mesenteric tissue, there was a highly significant increase in water content of the post-anastomotic samples compared to pre-anastomotic samples (P < 0.001) and a significant time treatment interaction was revealed (P < 0.05) suggesting an increase in oedema formation in the epidural local anaesthetic group. Lymph flow did not change during the experiments and there were no significant differences between the groups (P = 0.80). The mean total urine output was 44% higher in the epidural morphine group compared to the local anaesthetic group (P = 0.17).

Conclusions: Surgery did not increase gut wall water content, but acute oedema formation resulted in the peri-resectional mesenterial tissue, more prominently so in the bupivacaine group.

Summary

Background and objective: The expression of P-selectin on the surface of platelets and platelet–leucocyte conjugate formation are considered to be an indicator of platelet activation in thrombotic and inflammatory disease. Midazolam is a widely used sedative and anaesthetic induction agent. It may inhibit platelet aggregation and suppress interleukin-6 and -8 response in human leucocytes, but any effect on the adhesion of activated platelets to leucocytes remains obscure. We have examined the influence of midazolam on adenosine diphosphate (ADP)-induced platelet surface P-selectin expression and platelet–leucocyte aggregation in whole blood.

Methods: Human whole blood was stimulated with 2 × 10−5M ADP in the presence of midazolam (3 × 10−4 to 3 × 10−6M). Samples were stained with a fluorochrome-conjugated CD62P and CD41a antibody for detecting human platelet P-selectin antigens. The leucocyte subpopulations were separately gated and platelet–leucocyte aggregates were defined as cells found positive for CD45 and CD62P. All samples were analysed and were electronically separated into specific cell types (platelets, neutrophils, monocytes and lymphocytes) according to their typical forward/side scattering by flow cytometry.

Results: Midazolam significantly inhibited ADP-induced platelet P-selectin expression and attenuated platelet–leucocyte aggregation (mainly in neutrophils and monocytes) in a dose-dependent manner with a maximum inhibitory effect at 3 × 10−4M (P < 0.01).

Conclusions: This study demonstrated that midazolam decreases the ADP-induced expression of platelet surface P-selectin and platelet–leucocyte aggregation.

Summary

Background and objective: Neuromuscular block times, quality of muscle relaxation for tracheal tube insertion, and the haemodynamic effects after cisatracurium and vecuronium under sevoflurane–remifentanil anaesthesia were compared in elderly patients.

Methods: The study was performed in 40 patients over 65 yr of age. Anaesthesia was induced with thiopental, and maintained with sevoflurane in N2O/O2 and remifentanil. Cisatracurium 0.15 mg kg−1 or vecuronium 0.1 mg kg−1 were administered after induction. Intubation was attempted when neuromuscular block was 95%. Onset time, clinical duration of action, recovery index, spontaneous recovery time and tracheal intubation conditions were assessed. Haemodynamic parameters were also monitored.

Results: The average ages of the patients were 72.5 ± 5.1 and 73.6 ± 6.3 in the cisatracurium and vecuronium groups, respectively. Onset time was significantly shorter after vecuronium, 158 ± 34 s vs. 200 ± 50 s, respectively. Recovery index was significantly shorter after cisatracurium, 19.5 ± 7.5 s vs. 33.7 ± 18.6 s (P < 0.05). Clinical duration and spontaneous recovery time were similar in both groups as well as haemodynamic variables.

Conclusions: In elderly patients, vecuronium has a faster onset time while cisatracurium has a shorter recovery index under sevoflurane–remifentanil anaesthesia.

Summary

Background and objective: The time course of action of mivacurium does not correlate with its rapid breakdown by plasma cholinesterase. Pharmacokinetic–pharmacodynamic (PK–PD) modelling was applied to obtain more insight in the concentration–effect relationship.

Methods: Fourteen patients between 25 and 55 yr, undergoing non-major surgery, American Society of Anesthesiologists Grade I–II, were included. All patients received thiopentone/fentanyl/isoflurane/oxygen/nitrous oxide anaesthesia. Neuromuscular block was monitored mechanomyographically using single twitch stimulation (0.1 Hz). Mivacurium was administered as a short-term infusion, mean (standard deviation) duration 4.7 (1.0) min and dose 145 (33) μg kg−1. Arterial blood samples were obtained, and plasma was analysed using high performance liquid chromatography. PK–PD modelling was performed using an iterative Bayesian two-stage approach, assuming that the trans–trans and cis–trans isomers are equally potent.

Results: A PK–PD model with an effect compartment linked to plasma did not fit to the data satisfactorily. A model using an interstitial space compartment between plasma and effect compartment fitted significantly better. Parameters (mean (percentage coefficient of variation)) of the best fitting model were: kip 0.374 min−1 (46%), kei 0.151 min−1 (36%), EC50 98 μg L−1 (29%) and γ 3.7 (22%).

Conclusions: The PK–PD behaviour of mivacurium could be described using a model with an interstitial space compartment interposed between plasma and effect compartment. This model shows that the time course of mivacurium is mainly governed by the concentration decline in this interposed compartment and only indirectly related to the rapid plasma clearance.

Summary

Background: Changes in neutrophil and endothelial adhesion molecule expression occur during perioperative ischaemia and reperfusion (I/R) injury. We investigated the effects of lidocaine on neutrophil-independent changes in neutrophil and endothelial adhesion molecule expression associated with tourniquet-induced I/R.

Methods: Plasma was obtained from venous blood samples (tourniquet arm) taken before (baseline), during, 15 min, 2 and 24 h following tourniquet release in seven patients undergoing elective upper limb surgery with tourniquet application. Isolated neutrophils from healthy volunteers (n = 7) were pretreated in the presence or absence of lidocaine (0.005, 0.05 and 0.5 mg mL−1) for 1 h, and then incubated with I/R plasma for 2 h. Human umbilical vein endothelial cells (HUVECs) were pretreated in the presence or absence of lidocaine (0.005, 0.05 and 0.5 mg mL−1) for 1 h, and then incubated with the plasma for 4 h. Adhesion molecule expression was estimated using flow cytometry. Data were analysed using ANOVA and post hoc Student–Newman–Keuls tests.

Results: I/R plasma (withdrawn 15 min following tourniquet release) increased isolated neutrophil CD11b (P = 0.03), CD18 (P = 0.01) and endothelial intercellular adhesion molecule-1 (ICAM-1) (P = 0.008) expression compared to baseline. CD11b, CD18 and ICAM-1 expression on lidocaine (0.005 mg mL−1) treated neutrophils was similar to control. CD11b (P < 0.001), CD18 (P = 0.03) and ICAM-1 (P = 0.002) expression on lidocaine (0.05 mg mL−1) treated neutrophils and HUVECs was less than that on controls.

Conclusion: Increased in vitro neutrophil and endothelial cell adhesion molecule expression on exposure to plasma obtained during the early reperfusion phase is diminished by lidocaine at greater than clinically relevant plasma concentrations.

Summary

Background and objective: In this preliminary study we wanted to explore the attitudes of anaesthesiologists to a point-of-care information system in the operating room. The study was conducted as a preliminary step in the process of developing such a system by the European Society of Anaesthesiologists (ESA).

Methods: A questionnaire was distributed to all 2240 attendees of the ESA's annual meeting in Gothenburg, Sweden, which took place in April 2001.

Results: Of the 329 responders (response rate of 14.6%), 79% were qualified specialists with more than 10 yr of experience (68%), mostly from Western Europe. Most responders admitted to regularly experiencing lack of medical knowledge relating to real-time patient care at least once a month (74%) or at least once a week (46%), and 39% admitted to having made errors during anaesthesia due to lack of medical information that can be other-wise found in a handbook. The choice of a less optimal but more familiar approach to patient management due to lack of knowledge was reported by 37%. Eighty-eight percent of responders believe that having a point-of-care information system for the anaesthesiologists in the operating room is either important or very important.

Conclusions: This preliminary survey demonstrates that lack of knowledge of anaesthesiologists may be a significant source of medical errors in the operating room, and suggests that a point-of-care information system for the anaesthesiologist may be of value.

Summary

Background and objectives: This prospective, randomized, double-blinded study was designed to compare the effects of desflurane, isoflurane and sevoflurane when combined with remifentanil for induced hypotension on surgical conditions and operative field during tympanoplasty.

Methods: Sixty patients undergoing tympanoplasty were enrolled in the study. The patients were randomized into three groups of 20 each to receive the inhalation anaesthetics desflurane, isoflurane or sevoflurane. Propofol 2 mg kg−1 was administered for induction of anaesthesia in all groups. All patients received a continuous infusion of remifentanil which was titrated between 0.2 and 0.5 μg kg−1 min−1 to achieve a mean blood pressure (BP) of 60–70 mmHg. Nitroglycerine was infused if this BP could not be achieved. Arterial pressures were recorded continuously throughout the operation. Surgical conditions were assessed every 20 min by the blinded surgeon using a six-point category scale (0–5).

Results: One patient in the desflurane group and two patients in isoflurane group required nitroglycerine to maintain desired mean BP. Sustained controlled hypotension was sufficient in all of the groups throughout surgery. Category scale scores were ≤3 throughout the study, except one patient in the sevoflurane group who had a score of 4 at the 60th minute of the operation. No difference was found among groups when haemodynamic parameters and surgical category scale scores were compared. There were no postoperative respiratory and circulatory complications.

Conclusion: Desflurane, sevoflurane or isoflurane combined with remifentanil provided adequate induced hypotension and similar operating conditions and any of them could be safely and equally used in anaesthesia for tympanoplasty.

Summary

Background and objective: Cervical spine movement may be limited for morphological reasons or through injury. The major goal of the present study was to evaluate the three-dimensional cervical spine movement during intubation with a Macintosh or Bullard laryngoscope, a Bonfils fibrescope or an intubating laryngeal mask using an ultrasound-based motion system.

Methods: Forty-eight patients without any history of cervical spine problems who had to undergo elective surgery in general anaesthesia were intubated using a Macintosh or Bullard laryngoscope, a Bonfils fibrescope or an intubating laryngeal mask airway. During intubation, cervical motion as well as overall time to intubation, number of attempts, and postoperative complaints were noted.

Results: The range of cervical spine motion during intubation, especially concerning extension, using the Macintosh laryngoscope was much greater (22.5° ± 9.9°) than using Bullard (3.4° ± 1.4°), Bonfils (5.5° ± 5.0°) or intubating laryngeal mask (4.9° ± 2.1°). Time to intubate the trachea using Bonfils (52.1 ± 22.0 s) and intubating laryngeal mask (49.8 ± 18.7 s) were much longer than with Macintosh (18.9 ± 7.1 s) and Bullard laryngoscope (16.1 ± 6.2 s) (significance level: 0.05).

Conclusions: Our findings suggest that the Bullard laryngoscope may be a useful adjunct to intubate patients with cervical spine injuries. In elective situations when time to intubation is not critical Bonfils as well as intubating laryngeal mask airway should also be considered as serious alternatives to direct laryngoscopy.