Summary

Background and objective: Xenon reduces the infarct size after regional ischaemia in the rabbit heart in vivo, but the underlying mechanisms are unknown. Since adhesion molecules on neutrophils are closely involved in the pathophysiology of ischaemia/reperfusion injury and modulation of neutrophil function, we investigated the effect of xenon on neutrophil adhesion molecule expression in vitro.

Methods: Freshly isolated neutrophils were incubated with 30% or 60% xenon for 60 min. In unstimulated and after stimulation with either N-formyl-methionyl-leucyl-phenylalanine or phorbol-12-myristate-13-acetate neutrophil surface expression of PSGL-1, L-selectin, CD11a and CD11b were measured by flow cytometry.

Results: At both concentrations, xenon reduced the surface expression of PSGL-1 by 10% (P < 0.05), and of L-selectin by 15% (P < 0.05) in the 60% xenon group. Furthermore, N-formyl-methionyl-leucyl-phenylalanine activated neutrophils showed an increased removal of L-selectin from the neutrophil surface following incubation with xenon (30% compared to controls, P < 0.05). Neutrophil β2-integrin expression was not altered by xenon.

Conclusions: Xenon increases the removal of the selectins PSGL-1 and L-selectin from the neutrophil surface in vitro. Since both selectins are involved in the initial contact between neutrophils and endothelial cells, xenon may affect neutrophil adhesion to endothelium during ischaemia/reperfusion injury. However, because the β2-integrin expression was unaffected by xenon, further investigations are required to clarify whether xenon may modulate neutrophil transmigration through endothelial cells in vivo.

Summary

Background and objective: To compare the effects of sevoflurane and desflurane anaesthesia on lipid peroxidation.

Methods: We studied 40 healthy patients undergoing elective laparoscopic cholecystectomy. Patients were randomly allocated to be anaesthetized either with sevoflurane (n = 20) or desflurane (n = 20). Anaesthesia was maintained with inspiratory concentrations of sevoflurane 1–1.5 MAC (n = 20) or desflurane (n = 20). Samples were taken for plasma malondialdehyde and superoxide dismutase assays before induction of anaesthesia, before skin incision and at the end of surgery. Alveolar cell samples were obtained from the lungs using the technique of protective blind bronchoalveolar lavage, after induction of anaesthesia and at the end of surgery for malondialdehyde and superoxide dismutase concentrations.

Results: Plasma malondialdehyde increased more after the administration of desflurane than after sevoflurane: after induction 5.9 ± 0.6 nmol mL−1 for desflurane vs. 3.8 ± 0.5 nmol L−1 for sevoflurane (P < 0.001); at the end of the surgery: 6.7 ± 0.4 nmol mL−1 for desflurane vs. 4.2 ± 0.3 nmol mL−1 for sevoflurane (P < 0.001). There was a small but significant increase in plasma superoxide dismutase concentration after desflurane – from 24.2 ± 1.2 to 24.9 ± 0.9U mL−1 after induction and 25 ± 1U mL−1 at the end of the surgery (P < 0.01) but no increase with sevoflurane. Malondialdehyde concentrations increased significantly in the cells obtained by protective blind bronchoalveolar lavage at the end of surgery in the desflurane group (from 0.3 ± 0.1 to 1.7 ± 0.2 nmol mL−1 (P < 0.001)), but not in the sevoflurane group. There were no significant differences between the two anaesthetics in the amounts of superoxide dismutase in the samples obtained by protective blind bronchoalveolar lavage.

Conclusions: Desflurane may cause more systemic and regional lipid peroxidation than sevoflurane during laparoscopic cholecystectomy in healthy human beings.

Summary

Background and objective: Differences in sensitivity to anaesthetic drugs may exist among human races. Allelic variants for drug metabolizing isoenzymes and other pharmacokinetic/pharmacodynamic differences may account for a variable response to anaesthetic drugs. This study was designed to investigate comparatively the anaesthetic requirements and the recovery trends of three different ethnic groups: Caucasians, African blacks and Brazilians.

Methods: The anaesthetic depth and recovery of groups of 45 patients undergoing total intravenous anaesthesia with propofol and fentanyl were compared. The bispectral index and clinical parameters were used to assess the depth of anaesthesia. The bispectral index, the response to verbal stimuli and the eye opening time were used to assess recovery.

Results: After stopping propofol, the bispectral index values of Caucasians returned to the baseline in about 10.8 ± 4 min, that of Kenyan African blacks in 18 ± 7 min and that of Brazilians in a highly variable time ranging from 5 to 25 min, (14.9 ± 9.9). The time from discontinuation of propofol and fentanyl infusion to eye opening was 18.8 ± 7.1 min in African blacks (P < 0.01) and 13.5 ± 8.8 min in Brazilians (P > 0.05) vs. 11.6 ± 4.5 min in Caucasians. Time to respond to verbal commands was 16.8 ± 8 min in African blacks (P < 0.01) and 12.8 ± 8.1 min in Brazilians (P > 0.05) vs. 9.9 ± 4.5 min in Caucasians.

Conclusions: The recovery of Kenyan African blacks from anaesthesia with propofol and fentanyl is much slower, in comparison with Caucasians. The recovery time of Brazilians is much more variable, in comparison with Caucasians.

Summary

Background and objective: A randomized controlled trial of patients undergoing laparoscopic cholecystectomy. To evaluate whether the instillation of levobupivacaine, with epinephrine, intraperitoneally, reduces morphine consumption; further, to consider the degree of abdominal and shoulder pain in the presence of local anaesthetic at the site of surgical incision.

Methods: Patients received a standardized procedure and were allocated randomly to receive either (a) 2.5 mg mL−1 levobupivacaine 30 mL, with epinephrine 5 μg mL−1, or (b) normal saline 30 mL, with epinephrine 5 μg mL−1, to the bed of the gall bladder and above the liver, immediately before wound closure.

Results: Median (interquartile range) total abdominal pain during inspiration in the levobupivacaine group was significantly (P = 0.041) lower (71 (21–129) mm) than that in the placebo group (123 (71–179) mm). However, there was no significant difference between the two groups with respect to total abdominal pain at rest, right shoulder pain or the consumption of rescue morphine and rescue dihydrocodeine. There were no differences between the two groups with respect to the administration of cyclizine, total nausea and total sedation scores. In addition, the number of episodes of vomiting was not significantly different.

Conclusions: Intraperitoneal administration of levobupivacaine with epinephrine is associated with modest analgesia following laparoscopic cholecystectomy.

Summary

Background and objective: Isoflurane is a chiral volatile anaesthetic, routinely administered as racemate. It has a low metabolic rate and is mostly eliminated via respiration. In blood samples, S(+) enantiomers are found in greater proportion in the days immediately after administration of isoflurane racemate whereas the ratio in breath samples is unknown.

Methods: Breath and blood samples were drawn immediately after recovery and daily up to 19 days after operation from patients undergoing anaesthesia with isoflurane racemate. The percentage of isoflurane enantiomer was determined by gas chromatography mass spectrometry in blood and thermodesorption gas chromatography mass spectrometry in breath samples.

Results: In breath samples, there were significant differences in S(+) enantiomers at all time points compared to the racemate. During the early postoperative phase, the percentage of S(+) enantiomers were significantly enhanced whereas 5 days after surgery predominantly R(−) enantiomers (50.41%) were detected in the breath samples. Also in blood samples a statistical significant accumulation of the S(+) enantiomer was noted between days 1 and 5 compared to isoflurane racemate blood control. S(+) enantiomers were significantly higher in blood compared to breath samples and was most evident on the third day after surgery (51.43%).

Conclusions: During the first days after application of isoflurane racemate, the percentage of S(+) enantiomers are higher in breath and blood samples of patients. We suggest that resorbtion and/or redistribution of enantiomers are responsible for the different kinetics of isoflurane enantiomers.

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 aim: Rocuronium may be given to patients for intubation and also after they have received suxamethonium for intubation. The neuromuscular profile of rocuronium given after recovery from suxamethonium may not be identical to that when rocuronium has been given alone. The neuromuscular effects of suxamethonium and rocuronium, and their effects on intraocular pressure (IOP), heart rate (HR) and arterial pressure were also recorded.

Methods: Thirty patients were randomly allocated to receive either 0.6 mg kg−1 rocuronium (n = 15) or 1 mg kg−1 suxamethonium (n = 15) for intubation. Anaesthesia was first induced using propofol 2.5 mg kg−1 and fentanyl 2 μg kg−1 and maintained with propofol 6–12 mg kg−1h−1. The response of the thumb to supramaximal train-of-four (TOF) ulnar nerve stimulation at the wrist was measured using a mechanomyograph. In the suxamethonium group, when the first twitch of the TOF had recovered to 90%, rocuronium 0.6 mg kg−1 was administered. Before administration of relaxant, baseline readings of HR, arterial pressure and IOP were measured until stable, then the appropriate relaxant administered. Thereafter, all readings were repeated at 30, 90, 150, 210 and 270 s. Tracheal intubation was performed 300 s after the intubating dose and all recordings repeated 30 s later. Mechanomyographic monitoring was continued until 70% TOF recovery.

Results: Suxamethonium had a more rapid onset than rocuronium (49 s vs. 74 s, P < 0.0001). The onset time of rocuronium after suxamethonium was significantly reduced (56 s) and the time to recover to a TOF of 70% following rocuronium was increased by previous suxamethonium administration (47 vs. 58 min, P < 0.05). Suxamethonium caused a marked rise in IOP (>30%) and HR (>10%) while rocuronium had little effect on either.

Conclusion: Previous suxamethonium administration decreases the onset time and increases the duration of action of rocuronium. Unlike suxamethonium, rocuronium has few cardiovascular effects and causes little change in IOP.

Summary

Background and objective: Minimizing cervical vertebrae motion during endotracheal intubation is important in patients with cervical instability. The aim of this study was to compare upper cervical spine extension during endotracheal intubation using three different techniques.

Methods: Duration of intubation and movement of upper cervical vertebrae during endotracheal intubation were compared in 33 patients undergoing lumbar laminectomy. Patients requiring tracheal intubation under general anaesthesia and neuromuscular blockade were randomly allocated into three groups – direct laryngoscopy, intubating laryngeal mask (LM) airway and fibreoptic laryngoscopy. The procedure was recorded by video-fluoroscopy and analysed with computer-assisted measurements. The maximum movement of the C1/C2 and C2/C3 vertebrae during intubation were obtained. Data were analysed using one-way analysis of variance with Bonferroni and Kruskal–Wallis tests.

Results: We found statistically significant movement between the first and second, but not between the second and third cervical vertebrae. The mean (±SD) movement at C1/C2 was 10.2 ± 7.3° with direct laryngoscopy, 5.0 ± 6.3° with LM and 1.6 ± 3.2° with fibreoptic laryngoscopy. This difference was statistically significant (P = 0.01) between the direct and fibreoptic laryngoscopy groups. The maximum movement at C2/C3 was 2.2 ± 10.1° with direct laryngoscopy, 3.5 ± 5.1° with LM and 0.5 ± 3.2° with fibreoptic laryngoscopy. Duration of intubation was significantly longer in the intubating LM group (P < 0.001).

Conclusion: We conclude that fibreoptic laryngoscopy is the more suitable intubation technique when cervical spine movement is not desired.

Summary

Background and objective: One of the complications of laparoscopic surgery is carbon monoxide production during electrocautery. The aim of our study was to ascertain the relationship between intraperitoneal and alveolar concentrations of carbon monoxide and systemic carboxyhaemoglobin in patients undergoing laparoscopic cholecystectomy and anaesthetized with a closed system, where the carbon monoxide excreted through the lungs is accumulated in the circuit and thus re-inhaled.

Methods: Nine consecutive patients undergoing laparoscopic cholecystectomy were studied. Patients' lungs were ventilated with a closed anaesthesia breathing system (Physioflex®). Measurements were taken after establishing pneumoperitoneum (baseline) and at 5, 15 and 30 min after starting electrocautery.

Results: Mean duration of pneumoperitoneum was 42 ± 13 min with cumulative electrocautery time of 2.4 ± 1.8 min. Intraperitoneal carbon monoxide concentrations increased significantly at 5, 15 and 30 min reaching peak values of 481 ± 151 ppm at 15 min. No significant differences were found in alveolar carbon monoxide and carboxyhaemoglobin concentrations with respect to baseline.

Conclusions: No significant increase in carboxyhaemoglobin is produced during laparoscopic surgery, even under closed-system anaesthesia without pulmonary carbon monoxide elimination. This is most likely due to a low peritoneal absorption of carbon monoxide. We conclude that in adult patients, no carbon monoxide intoxication is caused if reasonable periods of electrocautery are used and the intraperitoneal gas is regularly renewed.

Summary

Background and objective: The P2X receptor is responsible for fast excitatory neurotransmission in the central nervous system. This receptor is suggested as one of the targets of volatile anaesthetics. The study was undertaken to examine the site of action of volatile anaesthetics, especially for P2X purinoceptor-mediated neurotransmission.

Methods: The effect of sevoflurane and isoflurane on [3H] α,β-methylene ATP binding was investigated in rat crude synaptic membranes. The crude synaptic membranes were prepared from Sprague-Dawley rat brains by centrifugation and then incubated with volatile anaesthetics or P2 receptor antagonists.

Results: [3H] α,β-methylene ATP binding was unchanged by either sevoflurane or isoflurane at clinically relevant concentrations. Suramin, a P2 antagonist, significantly (P < 0.05) decreased the binding of [3H] α,β-methylene ATP in a dose-dependent manner (68.7 ± 14.7% at 10 μmol, 49.5 ± 6.4% at 50 μmol, 24.3 ± 5.7% at 100 μmol, n = 10, mean ± SD), whereas pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS), another P2 antagonist, did not affect the binding.

Conclusions: The suppressive effect of volatile anaesthetics on ATP-mediated excitatory synaptic transmission could be one site of action. However, the blockade of ATP binding to P2X receptors is not a mechanism of action of volatile anaesthetics.

Summary

Background and objective: To determine if there is any significant difference between the effects of desflurane, isoflurane and sevoflurane on the QT interval, QT dispersion, heart rate corrected QT interval and QTc dispersion of the electrocardiogram.

Methods: The study was conducted in a prospective, double blind and randomized manner in a teaching hospital. Ninety ASA I patients, aged 16–50 yr, undergoing general anaesthesia for noncardiac surgery were studied.

Results: There was no significant change in QT intervals during the study in any group (P > 0.05). QT dispersion in the sevoflurane group 49 ± 14 ms vs. 37 ± 10 ms; in the desflurane group 55 ± 16 and 62 ± 21 ms vs. 35 ± 14 ms and in the isoflurane group 54 ± 26 and 59 ± 24 ms vs. 42 ± 19 ms were significantly increased at 3 and 10 min after 1 MAC of steady end-tidal anaesthetic concentration compared with baseline values (P < 0.05). QTc values in the sevoflurane group were 444 ± 24 and 435 ± 21ms vs. 413 ± 19 ms (P < 0.05), in the isoflurane group were 450 ± 26 and 455 ± 34 ms vs. 416 ± 34 ms (P < 0.05), in the desflurane group were 450 ± 26 and 455 ± 34 ms vs. 416 ± 34 ms (P < 0.05) at 3 and 10 min after reaching 1 MAC of anaesthetic concentration and significantly increased compared with baseline values. QTc dispersion increased significantly with sevoflurane 62 ± 14 ms vs. 45 ± 16 ms (P < 0.05); isoflurane 70 ± 36 ms at 3 min and 75 ± 36 ms at 10 min after reaching 1 MAC of anaesthetic concentration vs. 50 ± 24 ms (P < 0.05); desflurane 67 ± 25 ms at 3 min and 74 ± 27 ms at 10 min after 1 MAC concentration vs. 41 ± 22 ms (P < 0.05).

Conclusion: Sevoflurane, isoflurane and desflurane all prolonged QTd, QTc and QTcd but there were no significant intergroup differences.

Summary

Background and objective: To study the effect of age and other risk factors on: (a) the incidence and outcome of cardiopulmonary resuscitation and (b) any decision to institute a ‘Do Not Attempt Resuscitation’ order following cardiac surgery.

Methods: Prospective audit of cardiac arrest calls following 6550 consecutive open-heart surgery cases and retrospective audit of all cardiac surgical deaths not preceded by cardiac arrest calls.

Results: One-hundred-and-seventy-four patients (2.7%) had audited cardiac arrests of whom 70 (40%) survived to discharge. Elderly patients (≥70 yr old) had higher incidence of cardiac arrest (3.8% vs. 2%, P < 0.001). Survival to discharge following cardiopulmonary resuscitation was lower in the elderly patients, 33% vs. 48%, the difference approaching statistical significance (P = 0.06). Cardiopulmonary resuscitation was withheld in 46% of elderly vs. 40% of younger deaths (P = 0.40) which represented 3.1% of elderly vs. 1.2% younger patients (P < 0.001). Similar proportions of elderly (62%) and younger (67%) patients had failure of ≥3 organ systems on institution of the ‘Do Not Resuscitate’ order (P = 0.70).

Conclusion: ‘Do Not Resuscitate’ orders appeared twice as frequently in elderly patients (≥70 yr). However, the proportions of deaths without cardiopulmonary resuscitation and the organ failure scores between age groups were similar suggesting that severity of illness was more important than age in determining resuscitation status.

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: Our purpose was to evaluate the analgesic and sedative effects of intrathecal midazolam when added to spinal bupivacaine in patients undergoing perianal surgery under spinal anaesthesia.

Methods: Forty-four patients were randomly allocated into two equal groups: Group I (B) received hyperbaric bupivacaine 0.5% 2 mL + saline 0.9% 1 mL in a total volume of 3 mL intrathecally; Group II (BM) received hyperbaric bupivacaine 0.5% 2 mL + 1 mL of 2 mg preservative-free midazolam in a total volume of 3 mL intrathecally. In both groups, the onset and recovery times of sensory block, the degree and recovery times of motor block as well as the sedation and visual analogue pain scores were recorded, and statistically compared.

Results: In Group BM, the postoperative visual analogue pain scores were significantly lower at the first 4 h (P < 0.05), the average time until the first dose of additional analgesic requirement was significantly longer (P < 0.05), and sedation scales were significantly higher (P < 0.05), compared to Group B. There were no statistically significant differences in the onset and the full recovery times of sensory and motor blocks in the two groups.

Conclusion: The use of intrathecal midazolam combined with intrathecal bupivacaine produces a more effective and longer analgesia with a mild sedative effect in perianal surgery.

Summary

Background and objectives: Teaching is an important responsibility of non-consultant hospital doctors. In Ireland, specialist registrars (SpRs) in anaesthesia are contractually obliged to teach medical students, other doctors and nurses. Both medical students and fellow non-consultant hospital doctors attribute between 30 and 40% of their knowledge gain to non-consultant hospital doctors.

Methods: We carried out a confidential telephone survey of anaesthetic SpRs in Ireland regarding their current teaching practices and the perceptions of their role as undergraduate teachers. All the SpRs currently working in clinical practice in Ireland were eligible.

Results: Fifty-five of the 79 (70%) SpRs responded to the questionnaire. Only 7 (12.7%) of the respondents said they had been well trained as a teacher. The majority of the respondents stated that they would attend a learning-to-teach course/workshop if one was available, and felt that such a course would improve their ability as a teacher. Only 8 (14.5%) agreed that adequate emphasis is placed on commitment to teaching in the assessment of SpRs, both by individual departments and by the College of Anaesthetists. Anaesthetic SpRs in Ireland spend a considerable amount of time each day teaching undergraduate medical students, the majority (68.9%) stated that they had inadequate time to prepare for teaching.

Conclusion: The majority of the respondents stated that they enjoy teaching, feel that they play an important role in undergraduate teaching but have inadequate time to prepare for teaching. An adequate emphasis is not placed on their commitment to teaching.

Summary

Background and objective: Propofol may cause undesirable hypotension due to vasodilation. The underlying mechanisms are not completely understood. We investigated the mechanisms by which propofol relaxes vascular segments.

Methods: We studied the effect of propofol on isolated porcine coronary artery rings precontracted with potassium chloride or prostaglandin F2α.

Results: Propofol, in a concentration-dependent manner, relaxed all segments at concentrations of 5 μg mL−1 and above. This relaxation was unaltered in the presence of Nω-nitro-L-arginine, indomethacin, diltiazem 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 propofol (P < 0.001).

Conclusions: Our results suggests that the activation of the BKCa channel may contribute to the vasodilating effect of propofol, hereby causing hyperpolarization of the smooth muscle membrane and reduction of smooth muscle tone.