The importance of flow and pressure release in emergency jet ventilation devices

Background:  Several self-assembled devices, consisting of a three-way stopcock connected to a high pressure oxygen source, have been proposed for transtracheal jet ventilation in an emergency situation. As a three-way stopcock acts as a 'flow splitter' it will, when connected to a continuous oxygen flow, never ensure total flow and pressure release through its side port. The aim of the present study was to measure the efficacy of flow and pressure release of three previously described self-assembled jet devices and one commercially available tool.
Methods:  In a laboratory setting simulating an obstructed upper airway the generated pressure at the cannula tip (PACT) during the expiration phase was measured in three self-assembled jet devices consisting of a three-way stopcock with an inner diameter of 2 mm (device A), 2.5 mm (device B), and 3 mm (device C), respectively, and in the Oxygen Flow Modulator (OFM) at oxygen flows of 6, 9, 12, and 15 l·min⁻¹.
Results:  The PACT of device A at on oxygen flow of 15 l·min⁻¹ was 71.1 (±0.08) cm H₂O. At a reduced flow of 9 l min⁻¹ the PACT of device A was still 25.8 (±0.08) cm H₂O. In device B and C the PACT was 35.6 (±0.04) and 17.6 (±0.04) cm H₂O, respectively, at an oxygen flow of 15 l·min⁻¹. In contrast, the PACT in the OFM (five side holes open) was 4.4 (±0.02) cm H₂O at the same flow.
Conclusion:  In case of complete upper airway obstruction the OFM provides sufficient flow and pressure release, whereas the self-assembled jet devices tested are inherently dangerous constructions.     

Total intravenous anaesthesia with propofol and remifentanil in paediatric patients: a comparison with a desflurane-nitrous oxide inhalation anaesthesia

Background : Remifentanil is a new rapid-acting and ultra-short-acting μ-opioid receptor agonist with few reports from use in children. Therefore, we compared a propofol-remifentanil-anaesthesia (TIVA) with a desflurane-N₂O-anaesthesia (DN) with particular regard to the recovery characteristics in children.
Methods : 50 children (4–11 yr) scheduled for ENT surgery were randomly assigned to receive TIVA (n=25) or DN (n=25). After standardised i.v. induction of anaesthesia in both groups with remifentanil, propofol and cisatracurium, TIVA was maintained with infusions of propofol and remifentanil. Ventilation was with oxygen in air. DN was maintained with desflurane in 50% N₂O. The administration of volatile and intravenous anaesthetics was adjusted to maintain a surgical plane of anaesthesia. At the end of surgery all anaesthetics were terminated without tapering and early emergence and recovery were assessed. In addition, side effects were noted.
Results : Both anaesthesia methods resulted in stable haemodynamics but significantly higher heart rate with desflurane. Recovery did not differ between the groups except for delayed spontaneous respiration after TIVA. Spontaneous ventilation occurred after 11±3.7 min versus 7.2±2.8 min (mean±SD, TIVA versus DN), extubation after 11±3.7 min versus 9.4±2.9 min, eye opening after 11 ±3.9 min versus 14±7.6 min and Aldrete score ≥9 after 17±6.8 min versus 17±7.5 min. Postoperatively, there was a significant higher incidence of agitation in the DN-group (80% vs. 44%) but a low incidence (<10%) of nausea and vomiting in both groups.
Conclusion : In children, TIVA with remifentanil and propofol is a well-tolerated anaesthesia method, with a lower peroperative heart rate and less postoperative agitation compared with a des-flurane-N₂O based anaesthesia.     

Long-lasting infiltration anaesthesia by lidocaine-loaded biodegradable nanoparticles in hydrogel in rats

Background: Infiltration of a long-lasting anaesthetic is helpful during the post-operative period. The recently developed local drug delivery system, biodegradable nanoparticles in a thermo-sensitive hydrogel (nanogel system), may possibly provide an extended duration of drugs. Therefore, we evaluated whether prolonged infiltration anaesthesia could be achieved by loading lidocaine into this delivery system.
Methods: Thirty male rats were randomized into five groups of six rats each: saline; 2% hydrochloride lidocaine solution; lidocaine-loaded nanogel system and its compositing formulations, namely lido–nano gel; lido–nano; and lidogel. Durations of local anaesthesia with subcutaneously injected agents were measured by tail flick latency tests in a randomized, blind fashion.
Results: Lido–nano gel produced effective anaesthesia for 360±113 min, compared with 150±33 min by lidogel, 180±37 min by lido–nano, and 110±45 min by lidocaine solution ( P <0.001, means±SD), and elicited complete sensory blockade for 300±114 min, compared with 75±37 min by lidogel, 105±53 min by lido–nano, and 60±33 min by lidocaine solution ( P <0.001, means±SD) without severe skin/systemic toxicity.
Conclusion: Lidocaine-loaded biodegradable nanoparticles in hydrogel produced prolonged infiltration anaesthesia in rats without severe toxicity, indicating a possible way to develop long-lasting local anaesthetics.     

Propofol-fentanyl anaesthesia at high altitude: anaesthetic requirements and haemodynamic variations when compared with anaesthesia at low altitude

Background: There are few published accounts of anaesthesia delivery at high altitude. Natives at high altitude are known to have altered cardiorespiratory reserve. This study seeks to demonstrate the safety of propofol–fentanyl anaesthesia at high altitude titrated to the bispectral index (BIS) (3505 metres above sea level) in native highlanders. It also shows the differential effects of anaesthesia and surgery on the haemodynamics of such individuals as compared with individuals living at low altitude.
Methods: Fifteen consenting adults scheduled to undergo general surgical/orthopaedic procedures under general anaesthesia using fentanyl, and propofol infusions titrated to the BIS along with nitrous oxide in oxygen after intubation, were recruited in the high-altitude arm. Their anaesthesia record was compared with retrospective data from low altitude with respect to anaesthetic requirements, recovery after anaesthesia and the haemodynamic responses to surgical stress.
Results: The high-altitude dwellers required significantly larger doses of propofol at anaesthetic induction (2.31±0.64 vs. 1.41±0.24 mg/kg, P <0.0001) and thereafter to maintain designated BIS than their low-altitude counterparts (6.22±1.14 vs. 4.61±1.29 mg/kg/h, P <0.01). They, however, had uneventful and short recovery times. The high-altitude population also had significantly lower baseline heart rates (72±9.83 vs. 88±12.1, P <0.04) as also the heart rate responses to noxious stimulation such as direct laryngoscopy or skin incision ( P <0.04, P <0.005, respectively).
Conclusions: High-altitude dwellers require significantly larger amounts of intravenous anaesthetic propofol. Heart rate at rest as also the heart rate responses to surgical stress were significantly attenuated at high altitude.     

Leptin and perioperative neuroendocrine stress response with two different anaesthetic techniques

Background: Stress response to surgery is modulated by several factors, including magnitude of the injury, pain, type of procedure and choice of anaesthesia. Our purpose was to compare intra- and post-operative hormonal changes during total intravenous anaesthesia (TIVA) using propofol and remifentanil vs. sevoflurane anaesthesia in a low stress level surgical model (laparoscopy).
Methods: We randomly allocated 18 patients undergoing laparoscopic surgery for benign ovarian cysts in two groups to receive either TIVA (group A =9) or sevoflurane anaesthesia (group B =9). Perioperative plasma levels of norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), cortisol and leptin were measured. Blood samples were collected pre-operatively (time 0), 30 min after the beginning of surgery (time 1), after extubation (time 2), and 2 h (time 3) and 4 h after surgery (time 4).
Results: The comparative analysis between the groups shows significantly higher values of NE ( P <0.001 at time 1 and P <0.01 at time 3), E ( P <0.001 at times 1 and 2; P <0.01 at time 3 and P <0.05 at time 4), ACTH ( P <0.001 at times 1and 2; P <0.05 at time 3) and cortisol ( P <0.001 at times 1and 2; P <0.01 at time 3; P <0.05 at time 4) in group B .
The serum values of leptin were not significantly different between the two groups.
Conclusion: The choice of anaesthesia does not seem to affect the leptin serum levels but influences the release of stress response markers: ACTH, cortisol, NE and E.     

Blood volume is normal after pre-operative overnight fasting

Background: Pre-operative fasting is assumed to cause a deficit in intravascular blood volume (BV), as a result of ongoing urine production and insensible perspiration. Standard regimes consist of volume loading prior or simultaneous to any anaesthetic procedure to minimise the risk of hypotension. However, fluid overload in the context of major abdominal surgery has been shown to deteriorate patient outcome. Our study aimed to quantify total intravascular BV after fasting by direct measurements and to compare it with calculated normal values in comparable non-fasted patients.
Methods: After 10 h of fasting, total plasma volume (PV) and red cell volume (RCV) were measured via the double-label technique (indocyanine green dilution and erythrocytes labelled with fluorescein, respectively) following induction of general anaesthesia in 53 gynaecological patients suffering from malignoma of the cervix. The corresponding normal values were calculated individually from age, body height and body weight.
Results: Measured BV, RCV and PV after fasting were 4123±589, 1244±196 and 2879±496 ml, respectively. The differences to the corresponding calculated normal values were not significant (3882±366, 1474±134 and 2413±232 ml, respectively). The measured haematocrit reflected a slight anaemic state (0.35±0.03).
Conclusion: Our data suggest that even after prolonged pre-operative fasting, cardio-pulmonary healthy patients remain intravascularly normovolaemic. Therefore, hypotension associated with induction of general or neuraxial anaesthesia should perhaps be treated with moderate doses of vasopressors rather than with undifferentiated volume loading.     

Comparison between T-connecter and three-way stopcock as a portal for obtaining samples from indwelling catheter]

The accuracy of measurements on a sample obtained via either T-connecter or three-way stopcock connected directly with an indwelling catheter was comparatively evaluated. The sample was obtained through them after drawing glucose standard fluid (100 mg.dl-1) into a catheter which was primed with saline. The influence of sample volume and discarded volume on the glucose concentration in the sample was investigated, respectively. The results showed that both sample volume and discarded volume required smaller amount with a T-connecter than with a three-way stopcock to obtain more accurate measurements. The results also suggested that remaining discard aliquot in the connecting port of the three-way stopcock might influence the accuracy of the obtained sample when the sample volume was small.     

Insignificant effect of desflurane-fentanyl-thiopental on hepatocellular integrity--a comparison with total intravenous anaesthesia using propofol-remifentanil

BACKGROUND AND OBJECTIVE: Inhalational anaesthetics have been associated with hepatotoxicity. Even desflurane, with its low solubility in blood and tissues, and its minimal hepatic biotransformation, is known to affect hepatic integrity. The effects of propofol on hepatic function are, however, a matter of controversy. Alpha-glutathione S-transferase (alpha-GST), a sensitive and specific biomarker for hepatic integrity, was measured to assess the influence of total intravenous anaesthesia (TIVA) with propofol vs. anaesthesia with desflurane. METHODS: Forty-two patients scheduled for elective prostatectomy were randomly allocated to receive either desflurane, fentanyl and thiopental (desflurane group) or propofol and remifentanil (TIVA group). Depth of anaesthesia was guided by bispectral index. Plasma concentrations of alpha-GST and aminotransferases were measured before induction of anaesthesia (TO), at the end of surgery (T1), as well as 2 h (T2) and 24 h (T3) postoperatively. Haemodynamic parameters and bispectral index values were documented. RESULTS: alpha-GST increased significantly in the desflurane group from TO (3.0 +/- 2.2 microg L(-1)) to T1 and T2 (5.5 +/- 4.3 and 5.6 +/- 3.7 microg L(-1), respectively), whereas no changes were seen in the TIVA group. alpha-GST values above the normal upper limit (> 7.5 microg L(-1)) were seen in 24% of the patients receiving desflurane. Aminotransferases remained unchanged in both groups throughout the study period. CONCLUSIONS: The use of propofol as part of a TIVA regimen seems to have no influence on hepatocellular function during and after surgery. In contrast, patients receiving desflurane showed a transient slight, but significant, increase of alpha-GST to above the normal upper limit after anaesthesia, although this was without further clinical relevance.     

A simple, lightweight CPAP-delivery device, composed of a three-way stopcock, for the nondependent lung

Purpose  We aimed to introduce a simple, lightweight continuous positive airway pressure (CPAP)-delivery device for the nondependent lung during one-lung ventilation, to investigate how the type of three-way stopcocks, and the compliance and resistance of a test lung affect the relationship between the oxygen flow rate and CPAP level produced, and to examine how the device works in a clinical setting. Methods  In the test lung study, the bronchial blocker of a Univent tube was connected to a test lung. The effects of oxygen-flow rate, types of three-way stopcocks, and compliance and resistance of the test lung on the CPAP levels were studied. In the clinical study, the lightweight device was used to treat hypoxia in seven patients during one-lung ventilation with the bronchial blocker. Results  In the test lung study, the CPAP level produced by the device was proportional to the oxygen-flow rate, dependent on the type of three-way stopcock used, and independent of the compliance or resistance of the test lung. There was no discrepancy between the plateau pressures of the test lung and the monitoring port of an additional stopcock at any degree of compliance or resistance of the test lung at any oxygen-flow rate. Therefore, the relationship between the oxygen-flow rate and CPAP level can be ensured in advance before application to the lung, with an additional three-way stopcock of which the distal end is occluded. In the clinical study, peripheral oxygen sataration improved while the CPAP level ranged from 2.8 to 5.4 cmH₂O. Conclusion  The lightweight CPAP delivery-device can provide variable CPAP levels by adjusting the oxygen-flow rate without real-time monitoring of the pressure.     

Analgesia before a spinal block for femoral neck fracture: fascia iliaca compartment block

Background: In this prospective randomized study, the authors compared the analgesic effect of a fascia iliaca compartment (FIC) block with that of intravenous (i.v.) alfentanil when administered to facilitate positioning for spinal anaesthesia in elderly patients undergoing surgery for a femoral neck fracture.
Methods: The 40 patients were randomly assigned to one of two groups, namely, the FIC group (fascia iliaca compartment block, n =20) and the IVA group (intravenous analgesia with alfentanil, n =20). Group IVA patients received a bolus dose of i.v. alfentanil 10 μg/kg, followed by a continuous infusion of alfentanil 0.25 μg/kg/min starting 2 min before the spinal block, and group FIC patients received a FIC block with 30 ml of ropivacaine 3.75 mg/ml (112.5 mg) 20 min before the spinal block. Visual analogue pain scale (VAS) scores, time to achieve spinal anaesthesia, quality of patient positioning, and patient acceptance were compared.
Results: VAS scores during positioning (mean and range) were lower in the FIC group than in the IVA group [2.0 (1–4) vs. 3.5 (2–6), P =0.001], and the mean (± SD) time to achieve spinal anaesthesia was shorter in the FIC group (6.9 ± 2.7 min vs. 10.8 ± 5.6 min; P =0.009). Patient acceptance (yes/no) was also better in the FIC group (19/1) than in the IVA group (12/8)( P =0.008).
Conclusions: An FIC block is more efficacious than i.v. alfentanil in terms of facilitating the lateral position for spinal anaesthesia in elderly patients undergoing surgery for femoral neck fractures.     

Gene expression of pulmonary cytokines after sevoflurane or thiopentone anaesthesia in pigs

Background:  Volatile anaesthetics have diverse inflammatory effects on the lungs. They increase gene expression of some pro-inflammatory cytokines in alveolar macrophages whereas in alveolar type II cells they seem to decrease secretion and gene expression of pro-inflammatory cytokines. We have previously detected increased leukotriene C₄, nitrate and nitrite concentrations in bronchoalveolar lavage fluid after sevoflurane anaesthesia. In the current study, we measured gene expression of inflammatory cytokines in the lung tissue and plasma concentrations of cytokines in pigs after thiopentone or sevoflurane anaesthesia.
Methods:  Sixteen pigs were randomly selected to receive either a continuous thiopentone infusion (control group, n  = 8) or sevoflurane ( n  = 8) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Tissue samples were collected at the end of the study for measurement of gene expression of inflammatory cytokines. Blood samples were collected during anaesthesia for measurement of plasma cytokine concentrations.
Results:  Compared with thiopentone anaesthesia, lower gene expression of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in lung tissue was observed after sevoflurane anaesthesia. Of measured cytokines IL-1β, TNF-α, IL-6, IL-8 and IL-10 only plasma concentrations of IL-6 could be measured during the study without a difference between the groups.
Conclusion:  Lower gene expression of TNF-α and IL-1β was found in the intact porcine lung tissue after sevoflurane anaesthesia compared with thiopentone anaesthesia. Clinical significance of this finding is unknown.     

No inhibition of gastro-intestinal propulsion after propofol-or propofol/ketamine-N2O/O2 anaesthesia: A comparison of gastro-caecal transit after isoflurane anaesthesia

Background: Gastrointestinal motility may be considerably reduced by anaesthesia and or surgery resulting in postoperative ileus. Inhibition of propulsive gut motility is especially marked after an opioid-based technique. Little, however, is known of the gastrointestinal effects of the hypnotic propofol when given continuously over a longer period of time, which is the case in total intravenous anaesthesia (TIVA) and in intensive care sedation. We therefore set out to study the effects of a propofol-based nitrous oxide/oxygen anaesthesia (group PO) on gastro-caecal transit time. The results were compared with a propofol-ketamine technique (group PK) and an isoflurane-based anaesthesia (group I; each group n=20).
Methods: Gastro-caecal transit was determined by measurement of endexpiratory hydrogen concentration (ppm). Following gastral installation of lactulose at the end of the operation, the disacchharide was degraded by bacteria in the caecum, resulting in the liberation of hydrogen which was expired. A 100% increase in endexpiratory hydrogen concentration compared to the preinduction period was considered the end-point of gastrocaecal transit.
Results: There was no significant difference with regard to gastro-caecal transit in the three groups of patients. In the propofol group mean gastro-caecal transit was 119 (±50.6 SD) min, in the propofol-ketamine group it was 147 (±57.4 SD) min, and in the isoflurane group transit time was 122 (±48.6 SD) min.
Conclusion: The data suggest that propofol, even when given as a continuous infusion, does not alter gastrointestinal tract motility more than a standard isoflurane anaesthesia. The data may be particularity relevant to patients who are likely to develop postoperative ileus. They also suggest that in an ICU setting propofol does not alter gut motility more than a sedation technique with the analgesic ketamine.     

Propofol and alfentanil total intravenous anaesthesia: a comparison of techniques for major thoracic surgery

Background : Previous work has highlighted the disadvantages of propofol as a sole agent for total intravenous anaesthesia (TIVA). This randomised study investigated three combinations of propofol and alfentanil as TIVA for major thoracic surgery.
Methods : In 73 patients undergoing elective thoracic surgery, anaesthesia was conducted either with sodium thiopentone induction and inhalational maintenance (incorporating isoflurane) or with TIVA using propofol with alfentanil (by infusion at one of two rates or in incremental doses). Vital signs and recovery characteristics were recorded.
Results : There were no significant differences in heart rate or blood pressure between groups during either induction or maintenance. Depth of anaesthesia was controlled satisfactorily in all groups. Recovery characteristics were similar between treatment groups, although there was a trend towards earlier orientation
Conclusion : Continuous infusions of propofol and alfentanil provide safe and reliable TIVA for major thoracic surgery. TIVA was found to be a satisfactory technique in more elderly patients than previously described. The higher of the two alfentanil infusion rates may result in a better combination of propofol and alfentanil with respect to recovery times than the lower.     

Depth of anaesthesia monitoring in obese patients: a randomized study of propofol–remifentanil

Background: In obese patients, depth of anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that depth of anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil.
Methods: We investigated 38 patients with a body mass index ≥30 kg/m² scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer.
Results: Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group ( P =0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h ( P =0.24) and for remifentanil 2393 vs. 2708 μg/h ( P =0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight.
Conclusion: No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.     

Influence of acute normovolaemic haemodilution on bispectral index monitoring and propofol dose requirements

Background: Numerous medical and physiological conditions that might alter electroencephalography (EEG), such as hypoglycaemia, hypothermia or hypovolaemia, were shown to result in the bispectral Index (BIS) indicating an incorrect hypnotic state. Recently, acute normovolaemic haemodilution (ANH) was shown to be associated with significant impairment of cognitive functions that could alter EEG and consequently BIS monitoring, an EEG derived parameter.
Methods: In a randomised clinical study, we assessed the effect of ANH on BIS monitoring before induction and after propofol target controlled infusion (TCI) anaesthesia in 45 unmedicated patients randomly allocated to ANH with oxygen insufflation (oxygen group), ANH with air insufflation (air group), or control group.
Results: With ANH, mean BIS values briefly declined in the oxygen group (82±4) and air group (84±3) before returning to baseline values. The loss of consciousness time was significantly shorter, with fewer propofol TCI dose requirements, and BIS was significantly higher in the oxygen group (1.3±0.5 min, 2.41±0.15 μg/ml, 73±7) and air group (1.2±0.6 min, 2.44±0.17 μg/ml, 75±5), compared with the control group (1.7±0.4 min, 2.75±0.17 μg/ml, 61±5), respectively. Whereas, there was no significant difference in BIS values between the oxygen group (38±7), air group (36±5) and control group (40±6) at propofol TCI 4 μg/ml anaesthesia maintenance.
Conclusions: BIS values briefly declined with ANH before returning to baseline values before anaesthesia induction. Despite transient ANH enhancement of propofol effect during induction, there was no significant difference in BIS values with or without ANH during propofol maintenance of anaesthesia.     

Waste gas exposure during desflurane and isoflurane anaesthesia

Background : Currently, there are no data available concerning the occupational exposure to desflurane during general anaesthesia. This prospective, randomized study reports on occupational exposure to desflurane, compared to isoflurane, in a modern operation theatre (OT).
Methods : The study was performed in an OT equipped with a modern air-conditioning system and with a low-leakage anaesthesia machine connected to a central scavenging system. Trace concentrations of the anaesthetics were measured continuously by means of a photoacoustic infrared spectrometer during general anaesthesia in 30 patients undergoing eye surgery. Values were obtained within the breathing zone of the anaesthetist, the surgeon, the auxiliary nurse and at the mouth of the patient.
Results : Desflurane and isoflurane were administered with median (range) endtidal concentrations of 4.7 (3.8–10.3) vol% and 0.9 (0.6–1.4) vol%, respectively. The personnel-related median values of the average trace concentrations of desflurane and isoflurane were 0.5 (0.01–7.5) ppm and 0.2 (0.01–1.6) ppm, respectively.
Conclusions : Occupational exposure to desflurane is low in the environment of a modern OT, even though it has to be administered in approximately 5-fold higher concentrations compared to isoflurane.     

The optimal bolus dose of alfentanil for tracheal intubation during sevoflurane induction without neuromuscular blockade in day-case anaesthesia

Background: The purpose of this study was to determine the optimal bolus dose of alfentanil required to provide successful intubating conditions following inhalation induction of anaesthesia using 5% sevoflurane and 60% nitrous oxide without neuromuscular blockade in adult day-case anaesthesia.
Methods: Twenty-four adults, aged 18–60 years, undergoing general anaesthesia for short ambulatory surgery were enroled into the study. After vital capacity induction, with sevoflurane 5% and 60% nitrous oxide in oxygen, pre-determined dose of alfentanil was injected over 30 s. The dose of alfentanil was determined by modified Dixon's up-and-down method (2 μg/kg as a step size). Ninety seconds after the end of bolus administration of alfentanil, the trachea was intubated. Systolic blood pressure, heart rate and SpO₂ were recorded at anaesthetic induction, before, 1 min and 3 min after intubation.
Results: The bolus dose of alfentanil for successful tracheal intubation was 10.7±2.1 μg/kg in 50% of patients during inhalation induction. From probit analysis, 50% effective dose (ED₅₀) and ED₉₅ values (95% confidence limits) of alfentanil were 10.7 μg/kg (8.0–12.9 μg/kg) and 14.9 μg/kg (12.9–31.1 μg/kg), respectively.
Conclusions: Using the modified Dixon's up-and-down method, the bolus dose of alfentanil for successful tracheal intubation was 10.7±2.1 μg/kg in 50% of adult patients during inhalation induction using 5% sevoflurane and 60% nitrous oxide in oxygen without neuromuscular blocking agent in day-case anaesthesia.     

Target-controlled intravenous anaesthesia with bispectral index monitoring for thoracotomy in a patient with severely impaired left ventricular function

The anaesthetic management of an elderly patient with severely impaired left ventricular function undergoing thoracotomy and lobectomy is described. Total intravenous anaesthesia (TIVA) with remifentanil and target-controlled infusion of propofol titrated according to the bispectral index (BIS) was used, with thoracic epidural anaesthesia commenced at the end of surgery providing postoperative analgesia. Avoidance of intraoperative epidural local anaesthetics and careful titration and dose reduction of propofol using the BIS was associated with excellent haemodynamic stability. The rapid offset of action of remifentanil and low-dose propofol facilitated early recovery and tracheal extubation. The BIS was a valuable monitor in optimal titration of TIVA.     

Pulmonary inflammatory mediators after sevoflurane and thiopentone anaesthesia in pigs

Background:  Volatile anaesthetics have been shown to affect the release of pulmonary inflammatory mediators and exacerbate pulmonary injury after experimental aspiration. Thus, in theory, volatile anaesthetics may worsen inflammatory pulmonary injury and disease. We have previously described that no significant changes in alveolar ultrastructure are seen after sevoflurane anaesthesia. However, this does not exclude any possible physiological alterations. The aim of our study was to evaluate pulmonary inflammatory mediators in bronchoalveolar lavage (BAL) after sevoflurane and thiopentone anaesthesia in pigs with intact lungs.
Methods:  Sixteen pigs were randomly selected to receive either a continuous thiopentone infusion (control group, n = 8) or sevoflurane (n = 8) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Bronchoalveolar lavage samples were collected at the end of the study to determine pulmonary inflammatory markers.
Results:  Compared with thiopentone anaesthesia, significant increases in BAL leukotriene C₄ (LTC₄), NO₃-, and NO₂- levels were observed after sevoflurane anaesthesia. In addition, there was a significant decrease in total blood leukocyte count in sevoflurane-treated animals.
Conclusion:  We conclude that sevoflurane increases pulmonary LTC₄, NO₃-, and NO₂- production in pigs, indicating an inflammatory response.     

Pre-operative oral carbohydrate treatment before coronary artery bypass surgery

Background: Cardiac surgery is a stress that causes insulin resistance, which leads to an increase in insulin requirement. The aim of the present study was to evaluate the effect of a pre-operative oral carbohydrate drink vs. overnight fasting on perioperative insulin requirements in non-diabetic patients undergoing elective coronary artery bypass grafting (CABG) surgery.
Methods: One hundred and one patients scheduled for CABG were enrolled in the study. After fasting overnight, the patients were randomised into two groups. In the control group (C), no drink was given in the morning. In the treatment group (T), the patients ingested 400 ml of carbohydrate fluid 2 h before induction of anaesthesia. Blood glucose and insulin requirement was recorded. Gastric drainage was measured. Post-operative nausea and vomiting was recorded.
Results: Neither the number of patients requiring insulin nor the amount of insulin required to maintain normoglycaemia differed between the study groups. More patients in the treatment group experienced nausea post-operatively (26 vs. 16, P =0.044), but vomiting was equally common in the study groups (10 vs. 7). Intra-operative gastric drainage was 26.8±57.9 ml in the treatment group vs. 16±37.9 ml in the control group (NS).
Conclusion: In this study patient population, a pre-operative oral carbohydrate drink did not reduce post-operative insulin resistance or post-operative nausea and vomiting. According to our findings, it is safe to allow cardiac surgery patients to drink clear fluids up to 2 h before induction of anaesthesia, because gastric emptying of the drink was almost total and no aspiration occurred.