At clinically relevant concentrations, volatile anaesthetic agents influence neutrophil function. Our hypothesis was that sevoflurane would inhibit neutrophil apoptosis and consequently influence the postoperative pro-inflammatory state. In order to identify selectively the effect of the anaesthetic agent sevoflurane, we studied patients undergoing minimally stimulating (cataract) surgery randomly allocated to receive either sevoflurane (n=11) or local anaesthesia (n=12). Venous blood samples were taken immediately prior to anaesthesia and at 1, 8 and 24 h thereafter. The rate of neutrophil apoptosis, plasma concentration of cytokines and differential white cell count were measured. The rates of neutrophil apoptosis and plasma concentrations of IL-1β, TNF-α and IL-8 at each time point were similar in the two groups. IL-6 concentrations increased significantly and to a similar extent compared to preanaesthetic levels at 8 and 24 h. This study demonstrates that sevoflurane does not influence the rate of neutrophil apoptosis, cytokine concentrations and neutrophil count following cataract surgery.

Summary

Background and objective: Remifentanil has a short duration of action and constant elimination, which allow administration of high doses, without prolonging recovery. Remifentanil has been compared to alfentanil, as part of a total intravenous anaesthetic technique, where remifentanil provided better anaesthetic conditions than alfentanil, without adverse effect on recovery. However, these results were obtained during anaesthesia involving neuromuscular blockade, which may mask both signs of insufficient anaesthesia and side-effects such as muscle rigidity. The aim of this study was to compare remifentanil with alfentanil for anaesthesia without neuromuscular blockade.

Methods: We performed a prospective, randomized, double-blind, four-centre study to compare remifentanil infusion 15 μg kg−1 h−1 and alfentanil infusion 60 μg kg−1 h−1, using a total intravenous technique for non-paralysed patients, and the laryngeal mask airway for airway management. We enrolled 192 patients, 18–65 yr of age with ASA I–II, undergoing minor surgery. The primary endpoint was the number of patients having pre-defined responses to surgical stimulation. A number of secondary criteria was evaluated to assess undesirable properties of the procedures.

Results: In the alfentanil group, 85% of patients responded to surgical stimulation, vs. 35% in the remifentanil group (P < 0.0001). No difference was found in recovery data, or in any other parameter than those related to insufficient anaesthesia.

Conclusions: The remifentanil-based technique provided significantly better anaesthetic conditions than the alfentanil-based technique in the setting of this study, without causing any significant adverse effects.

Tracheostomy is necessary in intensive care unit (ICU) patients requiring prolonged mechanical ventilation. As an alternative to the standard surgical method, percutaneous techniques are available. Seventy-two patients were electively selected for percutaneous tracheostomy (PCT) in a nine-bed combined medical-surgical intensive care unit. PCT was performed at bedside with the Portex Percutaneous Tracheostomy Kit that uses the Griggs technique. The procedure time and early complications were recorded. The procedure was successful in all patients. The average duration of placement was 7.4 min. There were no tracheostomy-related deaths. Major bleeding occurred in three patients and required surgical intervention. In one patient, minor bleeding occurred at the stoma site that resolved with applied pressure. Wound infections were treated with local antiseptics in two patients. These findings suggest that PCT is a simple, quick and safe procedure.

Fifty-five consecutive patients undergoing a short-stay ophthalmic operation (orbital hydroxyapatite implantation) were recruited over 1 year to assess the frequency and duration of post-operative nausea and vomiting over 7 days. The incidence of nausea and vomiting in hospital was recorded. Patients scored their nausea and vomiting four times daily at home. By the end of the first day after surgery, 31 (75%) patients had experienced mild to severe nausea. Eighteen (38%) patients became nauseated on five or more occasions. Nineteen (35%) patients had vomited by the end of the first day after surgery and, over 7 days, 24 (43%) patients had vomited on one or more occasion. Three patients reported that they had vomited during the journey home. Vomiting was not correlated with pain or a past history of post-operative nausea and vomiting. However, there was a statistically significant correlation between nausea and pain. The high incidence of nausea and vomiting observed in this study appears to provide additional evidence of an oculo-emetic reflex. The timing of discharge and appropriate patient education are discussed.

Summary

Background and objective: The advantages of albumin over less costly alternative fluids continue to be debated. Meta-analyses focusing on survival have been inconclusive, and other clinically relevant end-points have not been systematically addressed. We sought to determine whether albumin confers significant clinical benefit in acute illness compared with other fluid regimens.

Methods: Database searches (MEDLINE, EMBASE, Cochrane Library) and other methods were used to identify randomized controlled trials comparing albumin with crystalloid, artificial colloid, no albumin or lower-dose albumin. Major findings for all end-points were extracted and summarized. A quantitative meta-analysis was not attempted.

Results: Seventy-nine randomized trials with a total of 4755 patients were included. No significant treatment effects were detectable in 20/79 (25%) trials. In cardiac surgery, albumin administration resulted in lower fluid requirements, higher colloid oncotic pressure, reduced pulmonary oedema with respiratory impairment and greater haemodilution compared with crystalloid and hydroxyethylstarch increased postoperative bleeding. In non-cardiac surgery, fluid requirements, and pulmonary and intestinal oedema were decreased by albumin compared with crystalloid. In hypoalbuminaemia, higher doses of albumin reduced morbidity. In ascites, albumin reduced haemodynamic derangements, morbidity and length of stay and improved survival after spontaneous bacterial peritonitis. In sepsis, albumin decreased pulmonary oedema and respiratory dysfunction compared with crystalloid, while hydroxyethylstarch induced abnormalities of haemostasis. Complications were lowered by albumin compared with crystalloid in burn patients. Albumin-containing therapeutic regimens improved outcomes after brain injury.

Conclusions: Albumin can bestow benefit in diverse clinical settings. Further trials are warranted to delineate optimal fluid regimens, in particular indications.

This study was undertaken to investigate the neuromuscular blocking profile and cardiovascular effects of Org 9487, a new aminosteroidal, non-depolarizing, neuromuscular blocking agent structurally related to vecuronium, in anaesthetized animals and in isolated muscle preparations. In in vitro functional assays of neuromuscular blocking activity, Org 9487 was between eight and 15 times less potent than vecuronium. In cats and monkeys the potency of Org 9487 was approximately one-seventh and one-twentieth, respectively, that of vecuronium. In both species, Org 9487 induced rapidly developing (onset times between 1.5 min and 1.9 min) neuromuscular paralysis, which was shorter-lasting than that of vecuronium and similar in time course to suxamethonium. The vagal: neuromuscular blocking dose ratio for Org 9487 was 3 and ganglion block was seen only at approximately 20 times the neuromuscular blocking dose. There was no evidence in the rat that Org 9487, administered at doses up to 3mg kg−1, inhibited noradrenaline re uptake. In anaesthetized dogs, Org 9487 (3 × 90% blocking dose) induced only relatively small and transient haemodynamic effects. The administration of clinically relevant doses of neostigmine or pyridostigmine shortened the time–course profile of Org 9487, even when administered during profound neuromuscular block. In animals, Org 9487 is a low potency, nondepolarizing neuromuscular blocking agent with a time course profile similar to that of suxamethonium. Although Org 9487 is less selective than vecuronium for the neuromuscular junction, it is unlikely to produce prohibitive cardiovascular side effects in man.

Summary

Background and objective: Since the moribund hypodynamic phase of septic shock has primarily been studied in small animal models, the objective of this study was to investigate the usefulness of infusing Salmonella typhosa endotoxin at incrementing doses to establish an ovine model of hypodynamic endotoxaemia.

Methods: In a prospective laboratory experiment, eight adult ewes were instrumented for a chronic study. Following a baseline measurement in the healthy state, a continuous endotoxin infusion was started with 10 ng kg−1 min−1 and was doubled every hour seven times. Haemodynamics, key variables of oxygen transport, and arterial lactate concentrations were determined every hour.

Results: In a dose-dependent manner, endotoxin infusion caused pulmonary hypertension, decreased cardiac output and mean arterial pressure, increased heart rate, and to a certain extent, systemic vascular resistance index. Following 4 h of endotoxaemia, the maximum decrease in cardiac output occurred (4.8 ± 0.2 vs. 7.6 ± 0.3L min−1; P < 0.001). This was accompanied by tissue dysoxia, represented by decreases in oxygen delivery (797 ± 20 vs. 1041 ± 28 mL min−1), oxygen consumption (277 ± 14 vs. 396 ± 15 mL min−1) and oxygen extraction rate (0.35 ± 0.01 vs. 0.38 ± 0.01%; each P < 0.01), as well as an increase in arterial lactate concentration (1.7 ± 0.1 vs. 0.7 ± 0.1 mmol L−1; P < 0.05).

Conclusions: This large animal model may be helpful to study the pathophysiology responsible for cardiovascular failure, and also new therapeutic approaches relevant to management of hypodynamic circulation in the common setting of progressed systemic inflammation.

Background and Objective To investigate the response to general anaesthetics of different sodium channel subtypes, we examined the effects of pentobarbital, a close thiopental analogue, on single sodium channels from human ventricular muscle and compared them with existing data from human brain channels.

Methods Sodium channels from preparations of human ventricular muscle were incorporated into planar lipid bilayers in the presence of batrachotoxin, a sodium channel activator. Single channel currents were recorded in symmetrical 100mmolL−1 and 500mmolL−1 NaCl before and after the addition of the anaesthetic pentobarbital (0.34–1.34mmolL−1).

Results The blocking effect of pentobarbital on the fractional open time had an IC50 of 690 μmol L−1 in 500 mmolL−1 NaCl, whereas it had a significantly lower IC50 of 400 μmol L−1 in 100 mmolL−1 NaCl. Pentobarbital caused a significant shift of steady-state activation to hyperpolarized potentials (fmax = −42 mV, IC50=2 mmolL−1). This effect was independent of NaCl concentration.

Conclusion Despite pharmacological and electrophysiological differences between human cardiac and human brain sodium channels their responses to pentobarbital are similar. The finding of channel block being dependent on the electrolyte concentration is novel for sodium channels.

All consultants and trainees in anaesthesia in a large teaching hospital were surveyed. Details of the number of flights per year and details of any medical emergencies in which they had been involved were recorded. The mean number of flights per year was 7.1 domestic and 3.4 international. Of the 45 anaesthetists surveyed, 14 had dealt with emergencies in flight, four had dealt with more than one. The minor emergencies (12) included transient ischaemic attacks, abdominal pain and otitis media. The seven serious events included seizures, angina, hypoglycaemic coma, respiratory arrest and two fatal cardiac arrests. No flights were diverted. On only two occasions were their medical qualifications checked. Requests for documentation were unusual. On several occasions the equipment which was available was inadequate. All doctors that responded were insured in the UK and most stated that they would assist Americans on American airlines. Medical emergencies were more likely on long haul flights.

The use of suppositories has been examined following a recent case in which an anaesthetist was reported to the United Kingdom General Medical Council. This study examined the preference for routes of administration of post-operative analgesia. A semi-structured interview with a written questionnaire was administered to 610 subjects (49 doctors; 62 nurses; 67 paramedical staff; 44 other hospital employees; 388 patients). Four hundred and fifty (74%) preferred the intravenous (i.v.) route, 24 (4%) preferred a suppository while 136 (22%) found either route acceptable. The i.v. route was most popular with young (98% under 20 years) females (79%) social class I subjects (90%), doctors (96%), nurses (95%), those who had never had a suppository (81%) and those who had ill effects following a previous suppository (95%). This result suggests that patients are more tolerant of suppositories than hospital staff but the majority prefer the i.v. route.

Summary

Background and objective: Data from several studies implicate that pre-treatment with non-selective cyclooxygenase inhibitors such as aspirin or diclofenac may decrease the incidence of postoperative succinycholine-related myalgia. We tested the influence of a preoperatively administered selective cyclooxygenase 2 inhibitor, parecoxib, on postoperative myalgia. Methods: After Ethics Committee approval, 68 patients were randomized into two groups (n = 34 each). Group 1 received parecoxib 40 mg intravenously 3 min before induction of anaesthesia, and Group 2 received saline (in a double-blinded manner). Incidence and severity of myalgia was evaluated systematically with a standardized questionnaire 24, 48 and 72 h after anaesthesia. We also the assessed the number of patients who felt limited in their activity due to myalgia. Results: Seven patients in the parecoxib-treated group complained of myalgia compared with 11 in the control group (not significant). No significant difference in the severity of myalgia or in the limitation of patients activity was found between the groups. Conclusion: Intravenous parecoxib 40 mg, when administered before induction of anaesthesia, did not reduce incidence and severity of postoperative myalgia and did not improve activity in those who suffered from myalgia.

Summary

Background and objectives: This study was designed to quantify the additional postoperative analgesic efficacy of a single dose of ketoprofen in patients undergoing thyroid surgery using two different intraoperative analgesic regimens. Methods: One hundred and twenty patients were randomly assigned to one of four groups: intraoperative fentanyl or remifentanil with or without ketoprofen (n = 30 for each group). Intravenous ketoprofen (1.5 mg kg−1) or saline was administered 45 min before the end of surgery. Pain scores, opioid demand and length of stay in the postanaesthesia care unit were assessed in a blinded manner. Results: Patients receiving intraoperative fentanyl with saline had significantly lower visual analogue scale pain scores in the postanaesthesia care unit compared with those receiving intraoperative remifentanil with saline (55 ± 10 mm vs. 80 ± 18 mm, P < 0.05) and they stayed shorter in the postanaesthesia care unit (86 ± 24 min vs. 126 ± 37 min). In conjunction with intraoperative fentanyl, ketoprofen significantly decreased postoperative pain scores (40 ± 10 mm, P < 0.05 compared with fentanyl alone) and opioid demand (4 of 30 patients vs. 14 of 30 patients compared with fentanyl alone, P < 0.05). Patients receiving intraoperative remifentanil had no additional analgesic benefit with ketoprofen. Conclusion: After thyroid surgery, patients receiving intraoperative fentanyl had lower pain scores and needed less rescue analgesia compared with patients receiving intraoperative remifentanil. The adjunction of ketoprofen further improved analgesia in patients who received intraoperative fentanyl only.

Lignocaine added to the anaesthetic preparation Diprivan® reduces propofol induced pain on injection. This effect is due to a drop in pH which decreases the content of propofol in the aqueous phase of the soya bean emulsion. This in turn changes the electrostatic forces in the emulsion and destabilization occurs. The effect of lignocaine on the anaesthetic potency of propofol was validated in a randomized blind study in the rat. The induction dose of 1% propofol mixed with 1% lignocaine (10+1) was significantly higher when compared with the induction dose of propofol 1% given after a separate injection of 1% lignocaine (9.4±5.5 vs. 5.6±5.2 mg; P<0.05). The duration of sleep was shorter in rats injected with propofol 1% mixed with lignocaine 1% (10+1) compared with those given 1% lignocaine and 1% propofol in separate injections (160±181 vs. 375±202 s; P<0.05). The anaesthetic potency of propofol was not significantly changed by the addition of either saline or hydrochloric acid. The anaesthesia inducing effect was not time-dependent. A similar lower potency was observed for a solution stored for 4 h compared with one freshly prepared, although sleeping time was longer (9.2±6.8 mg; 428±110 s) as compared with the 4 h mixture. The results indicate that lignocaine altered the propofol preparation. The reduced anaesthetic potency of propofol after addition of lignocaine is not due to the resultant drop in pH, which is known to occur.