A number of methods exist by which the pH of local anaesthetic solutions may be increased. Most commonly, these require the addition of differing amounts of sodium bicarbonate solution according to the local anaesthetic drugs. Sodium bicarbonate (1%) was titrated against pH in six commonly used local anaesthetic solutions. Titration curves of pH and volume of sodium bicarbonate solution added are shown for this group of local anaesthetics. This study demonstrates that 1 mL of 1% sodium bicarbonate solution may be used to alkalinize this range of local anaesthetics without the risk of precipitation. We also conclude that Ropivacaine (at concentration 0.75% and 1.0%), is unsuitable for alkalinization since it precipitates at a pH of 6.0.

Tramadol is a weak centrally acting analgesic and it might provide efficacious postoperative pain relief with minimal sedative effects in the use of intravenous patient-controlled analgesia (PCA). Sixty women scheduled to undergo microvascular breast reconstruction under standard general anaesthesia were enrolled in a study on the performance of patient-controlled analgesia with tramadol or morphine with special emphasis on drug- and technique-related side-effects. Seven patients were re-operated within the same day, leaving 25 patients in the tramadol group and 28 in the morphine group for comparison. When postoperative pain occurred, loading doses of either 10mg tramadol or 1mg morphine intravenous increments were administered in a double-blind fashion until the pain control was judged to be satisfactory by the patient. After that the patients received tramadol or morphine by a PCA apparatus (lockout 5 min, tramadol 450 μg kg−1, morphine 45 μg kg−1 bolus). In addition, all patients received 500mg paracetamol rectally, three times a day. The potency ratio of tramadol to morphine was found to be between 8.5 : 1 (loading) and 11 : 1 (PCA). There was neither a significant difference between the groups in the overall satisfaction of the analgesic medication nor in the visual analogue and verbal rate scales for pain. Women in the tramadol group had more nausea and vomiting during the administration of loading doses (P < 0.05) and more patients in the tramadol group (7) than in the morphine group (3)(NS) wanted to discontinue the PCA therapy before the end of the study due to nausea. Sedation or blurred vision prevented the performance of the psychomotor tests in 22 and 32% of the tramadol and morphine patients, respectively. The remaining patients performed similarly in the Digit Symbol Substitution Test. In women receiving intravenous PCA for analgesia after microvascular breast reconstruction tramadol and morphine provided comparable postoperative analgesia with similar sedative effects. However, tramadol was associated with a disturbingly high incidence of nausea and vomiting.

In a double-blind randomized study, the incidence and severity of postoperative nausea and vomiting was investigated with a new formulation of etomidate (Etomidate-®Lipuro, B. Braun Melsungen AG, Germany) compared with propofol for induction of a balanced anaesthesia with isoflurane/fentanyl in air.

The incidence and intensity of nausea was examined by use of a visual analogue scale (VAS; 0–100 mm) at 1, 2, between 6 and 8, and 24 h postoperatively. One-hundred-and-sixty-four patients undergoing orthopedic procedures were studied. For etomidate vs. propofol, 14.6% vs. 14.2% male and 26.8% vs. 27.5% female patients were nauseated during the first two postoperative hours. The median rating for nausea remained below 5 mm at any time in both groups, i.e. the intensity of nausea was very low. The incidence of vomiting was higher in women receiving etomidate (26.8% vs. 10%).

We conclude that etomidate does not increase nausea during the early postoperative period.

Clevidipine is a new lipophilic, ultra-short acting 1,4-dihydropyridine calcium channel antagonist for intraoperative use. Because sarcolemnal calcium currents are involved in the mechanism of action of anaesthetics we questioned whether clevidipine alters the potency of volatile anaesthetics. We studied the effects of clevidipine on minimal alveolar concentration and the time to awaken from isoflurane anaesthesia. Sprague-Dawley rats were anaesthetized with isoflurane, and were allocated to one of four treatments prior to minimal alveolar concentration determination: (a) saline control; (b) clevidipine 20 nmol kg−1 min−1; (c) clevidipine 40 nmol kg−1 min−1; (d) clonidine 1 μg kg−1 – positive control. Ten mongrel dogs were anaesthetized with isoflurane and received a continuous infusion of clevidipine 6 nmol kg−1 min−1 or the solvent (Intralipid 20% – control). After 2 h of steady-state anaesthesia, minimal alveolar concentration awake and the time to awakening were recorded. Clevidipine reduced minimal alveolar concentration to a small but statistically significant extent (from 1.40±0.16 control to 1.23±0.13 vol% with 20 nmol kg−1 min−1 and to 1.27±0.12 vol% with 40 nmol kg−1 min−1; mean±SD; P < 0.05) in rats. Clonidine reduced minimal alveolar concentration to 0.90±0.17 vol% (mean± SD; P < 0.05). Minimal alveolar concentration awake and the duration of sleep were not affected by clevidipine in dogs. Clevidipine mildly reduces miinimal alveolar concentration of isoflurane but does not prolong the duration of sleep and does not affect minimal alveolar concentration awake after a 2-h steady-state isoflurane anaesthesia.

Fibreoptic bronchoscopy is often used to diagnose tracheomalacia under local anaesthesia. However, in children, general anaesthesia may be required due to difficulty in obtaining co-operation. A 1-yr-old girl with a suspected congenital tracheomalacia was scheduled for diagnostic fibreoptic bronchoscopy. During induction of anaesthesia by inhalation of increasing concentration of sevoflurane, spontaneous breathing became irregular and a partial airway obstruction occurred. Because vecuronium relieved the airway obstruction, the airway was managed using a laryngeal mask. No further airway obstruction occurred during fibrescopy under controlled ventilation, but when spontaneous breathing resumed, marked airway obstruction occurred. The trachea was intubated immediately. Caution is required to manage the airway without tracheal intubation during general anaesthesia in the patient with tracheomalacia.

The delivery of an hypoxic gas mixture to a patient during general anaesthesia is a rare event due to contemporary standards of monitoring, equipment design and alarm features. An incident is described where a split occurred in a rubber seal round the top of a flowmeter control tube. This resulted in a downstream oxygen leak and the delivery of an hypoxic gas mixture to the patient. The bobbin on the oxygen flowmeter did not accurately reflect the amount of oxygen being delivered. A paramagnetic oxygen analyser and a fuel cell oxygen electrode indicated that the inspired oxygen concentration was lower than intended. The anaesthetic machine was exchanged, and the operation continued uneventfully. The faulty anaesthetic machine subsequently passed a formal pressure test by the hospital engineers and also close examination of the flowmeter control valves. The importance of monitoring equipment and the interpretation of the information that they provide is emphasized.

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.

This study was designed to determine the efficacy of oral etilefrine in preventing hypotension induced by spinal anaesthesia. Forty patients, ASA grade I or II, aged 23–60 years, scheduled for orthopaedic surgery involving the lower extremity under spinal anaesthesia were studied. The patients were randomly allocated to one of two groups; the etilefrine group (n=20) received oral etilefrine 15mg (30 drops), 60 min before the subarachnoid lock, and the control group (,n=20) received no etilefrine. Patients were given 0.5% isobaric bupivacaine intrathecally. Hypotension was defined as a 30% decrease from base-line for systolic arterial pressure and mean arterial pressure or systolic value <90mmHg, and was treated with intravenous boluses of etilefrine 2 mg. The overall incidence of spinal anaesthesia induced hypotension was 25%, ranging from 20% in the etilefrine group to 30% in the control group. The fall in systolic arterial pressure and mean arterial pressure was significantly greater in the control group than in the etilefrine group (P < 0.05). The patients in the etilefrine group received less etilefrine supplement than those in control group and no subject in the etilefrine group required repeat etilefrine doses, while in the control group five patients received multiple etilefrine doses (P < 0.05). The mean heart rate remained fairly stable throughout the study periods. We conclude that oral etilefrine, given 60 min before surgery, reduces the fall in blood pressure during spinal anaesthesia.

We have used a remifentanil-based anaesthetic for patients undergoing major abdominal surgery who would normally have gone to the intensive care unit in this hospital. Avoiding intensive care unit admission was considered an advantage as a shortage of intensive care unit beds was leading to the cancellation of operations. We first used remifentanil as part of a safety and efficacy study. The aim was to see if the rapid and complete awakening obtained when using this drug would allow us to avoid the need for admission to an intensive care unit and use a high dependency unit instead. This was shown to be practicable. In comparison with a group of patients matched retrospectively for the type of operation before remifentanil was used there was a reduction in the length of time (mean ± SD) patients’ lungs were ventilated (612 ± 417 vs. 9.9 ± 28.9 min P<0.0001). There was no saving in cost (£808.71±£187.06 vs. £795.27±£253.49). When remifentanil was used routinely (after the safety and efficacy study), there were significant reductions in the time to tracheal extubation (612±417 vs. 4±10 min P <0.0001) and costs (808.71I vs. 392.10 I P <0.0001) compared with other patients in whom it was not used. Patients waiting for a liver transplant were also being cancelled when a donor organ became available because of the shortage of intensive care unit beds. Based on our other experience with remifentanil, we used a similar anaesthetic technique for these patients. It proved possible to extubate the trachea in 12 of 15 patients at the end of the operation. No patient needed re-intubation. The need for intensive care and therefore cancellation of surgery was reduced. In contrast, only one patient's trachea was extubated immediately after surgery in the group of patients anaesthetized before the introduction of remifentanil. A remifentanil-based technique in combination with a change in organization has therefore enabled us to avoid admission to the intensive care unit for these patients.

The failure of anaesthetic equipment as a result of maintenance is extremely rare. The ingress of water into the flowmeters of an anaesthetic machine from the piped medical air supply is reported and is possibly unique. The piped medical air supply was open to the atmosphere during maintenance. Water condensed in the gas pipeline and this was not noticed during subsequent testing. Water was seen leaking from the orthopaedic air tools used for surgery but was assumed to be from the autoclaving process. Later the same day, when medical air from the piped source was used as part of the gas mixture for a general anaesthetic, water was seen filling the barrel of the flowmeter air control valve. This could have had far-reaching and dangerous consequences for the patient, which were fortunately averted.

We have studied the acid-base equilibrium in 12 patients with end-stage renal failure (ESRF) during capnoretroperitoneoscopic nephrectomy. Bupivacaine (12 mL, 0.375%) and morphine (2 mg) were given in the lumbar epidural space, and fentanyl (0.5 μg kg−1) and midazolam (50 μg kg−1) were given intravenously. Anaesthesia was induced by thiopental, maintained with halothane carried by oxygen enriched air (inspired oxygen fraction = 0.35), and ventilation was achieved with a tidal volume of 10 mL kg−1 at a rate of 12 min−1. This procedure resulted in a mild degree of respiratory acidosis that was cleared within 60 min. We conclude that capnoretroperitoneoscopic nephrectomy can be performed in patients with end-stage renal failure with minimal transient respiratory acidosis that can be avoided by increased ventilation.

A telephone survey of 20 English intensive care units (ICUs) confirmed that visual estimation of patient weight is often performed. Four experienced intensive care staff (three doctors and one nurse) estimated the weight and measured the height of 30 volunteers and the estimates were compared with accurate reference measurements. The estimates were shown to be significantly inaccurate for individual observers. We consider the degree of inaccuracy to be of clinical importance. However, pooling the individual estimates of weight as mean values improved accuracy. Recommendations are made concerning the performance of height and weight determination.

Nimodipine, a calcium channel blocking drug, is used in the treatment of cerebral arterial spasm after subarachnoid haemorrhage due to bleeding from an intracranial aneurysm. The purpose of this study was to evaluate the effects of nimodipine on neuromuscular blockade after vecuronium had been given to facilitate tracheal intubation and maintenance of muscle paralysis in patients undergoing clipping of intracranial aneurysm. Twenty patients were divided into two groups: a control group (n = 10) who received no calcium channel blocking drug, and a nimodipine group (n = 10) consisting of patients treated with nimodipine at clinically used doses of 0.03 mg kg−1 h−1 pre- and perioperatively. Anaesthesia was induced with atropine 10 μg kg−1, dehydrobenzperidol 5 mg, fentanyl 5 μg kg−1, thiopental 5 mg kg−1 and maintained with a mixture of N2O and isoflurane (0.5–1% inspired concentration) in O2, and additional doses of fentanyl 2.5 μg kg−1. Neuromuscular responses were monitored by acceleromyograpy. The first twitch of the train-of-four response (T1) was considered as twitch height.After a stabilization period, an intubating dose of vecuronium 0.1 mg kg−1 was administered. The onset of action, the time of first appearance of T−1 and clinical duration of action were recorded. Then, maintenance doses of vecuronium 0.03 mg kg−1were administered twice more when T1 had recovered to 25% of control twitch height. The study ended when the recordings of the 3rd 25% T1 recovery had been obtained. There were no statistical differences in the onset time (120±44 s in the control group, 141±33 s in the nimodipine group), in the first appearance time of T1 (28±6 min in the control group, 30±8 min in the nimodipine group), and in the times for 25% recovery in T1 (41±11, 32±2, 40±13 min in the control group, respectively, and 44±16, 36±15, 38±15 min in nimodipine group, respectively) between the groups studied. The time between the injection of the intubating dose of vecuronium and the third recovery of T1–25% of control was not significantly different between the control group (113±34 min) and the nimodipine group (117±42 min). This study indicates that nimodipine does not have any significant effect on the time course of action of vecuronium including the onset time and its clinical duration of action after the initial and the two maintenance doses in these patients.

A 45-year-old man with cryptorchism, who was known to suffer from generalized myasthenia gravis, was admitted to hospital for surgical treatment using laparoscopy. Such minimally invasive surgery requires good muscle relaxation. However, the use of neuromuscular blocking agents in patients with myasthenia gravis may lead to prolonged apnoea after operation, thus necessitating mechanical ventilation of the lungs. We used a combination of general anaesthesia (with desflurane), and epidural anaesthesia (with the amide local anaesthetic ropivacaine) to obtain excellent abdominal relaxation during surgery. Tracheal extubation was possible immediately after the operation and no adverse effects were observed. The patient was discharged from hospital on the second day after operation. The combination of regional and general anaesthesia for minimally invasive surgery in this patient permitted safe anaesthetic management.

In order to prescribe appropriate analgesia for burns dressing changes the pain experienced by 30 burned patients during this procedure was recorded. Patients received analgesia prior to their dressing changes according to the current protocol in the burns unit. During the same period the medical and nursing staff in the unit who were involved in prescribing and administering the analgesia for the dressing change, were asked to assess the severity of pain that they thought patients experienced during dressing changes. Patients recorded their worst pain as none or mild in 64% of procedures. In contrast, no surgeon and only one nurse, rated pain as none or mild. The discrepancy between severity of pain recorded by patients and the pain predicted by staff prescribing and administering analgesia has clinical implications.

We present a case of pulmonary embolism that occurred during the injection of lipiodol during transcatheter arterial chemoembolization under general anaesthesia. A 7-year-old child suffering from a large hepatoblastoma was admitted for arterial chemoembolization and carcinostatic administration. Pulmonary embolism due to lipiodol during arterial chemoembolization was evident by a sudden fall in oxyhaemoglobin saturation from 100 to 90%. This was associated with a spread of lipiodol into both lungs, particularly the middle lung zones and detected by chest fluoroscopy. Arterial blood gases returned to normal values 1 day later but pulmonary infiltration persisted for 7 days before final clearance. Pulmonary embolism caused by lipiodol during arterial chemoembolization is infrequent, but such a complication could prove fatal. Understanding the risk of pulmonary embolism in patients receiving lipiodol, during and after arterial chemoembolization, and late onset pulmonary injury is important and a close follow-up for several days after arterial chemoembolization is advisable.

We describe the satisfactory use of combined spinal epidural (CSE) anaesthesia in the management of a 29-year-old paraplegic woman, with a spinal cord lesion at the T7 level, suffering from episodes of autonomic hyper-reflexia, during elective Caesarean section.

We evaluated the ability of inexperienced personnel in using a prototype illuminated flexible catheter to assist tracheal intubation through the intubating laryngeal mask in anaesthetised, paralysed patients. The device consists of a completely flexible thin plastic catheter, a bulb attached to its distal end and a 15-mm concentric adapter at its proximal end. The illuminated catheter is placed into a straight silicone tracheal tube in such a way that the bulb is placed at the distal end of the tracheal tube. Six nurses inexperienced in tracheal intubation followed a 2-hr training program by using the device through the intubating laryngeal mask in a mannequin and then intubated 10 patients each, with instruction from an anaesthetist. All patients (n = 60) were ASA 1–2, scheduled to undergo general anaesthesia for elective surgery. After fentanyl/propofol induction the intubating laryngeal mask was inserted. When an adequate airway was established, patients received atracurium and the endotracheal tube preloaded with the device was inserted through the intubating laryngeal mask and by observing the glow in the neck was advanced into the trachea. The final outcome and the duration of the procedure were recorded. The intubating laryngeal mask was inserted successfully in all patients. The success rate of intubation was 57/60 (95%); 38 patients at first attempt and 19 after two or three attempts. The mean (±SD) duration of the procedure in the first five patients in the series of each nurse was 74±40 s while in the last five patients it was diminished to 52±23 s (P= 0.01). We conclude that the described methodology has the potential for more widespread use of tracheal intubation through the intubating laryngeal mask even by inexperienced personnel.