Cardiac arrest is a dramatic condition leading to sudden death if someone cannot perform two interventions, basic life support and early defibrillation, that have been proved to improve long-term survival. The modern era of cardiopulmonary resuscitation began with a description of closed chest cardiac massage by Kouwenhoven in 1960. Research to make advances in cardiac arrest is a very difficult task. Experts set up a series of guidelines that represent a keystone for educational needs and evolving technology. There is a consensus that the highest potential survival rate from cardiac arrest can only be achieved when the following sequence of events occurs as rapidly as possible: (1) recognition of early warning signs, (2) activation of the emergency medical services, (3) basic cardiopulmonary resuscitation, (4) cardiac defibrillation, (5) management of the airway and ventilation of the lungs, and (6) intravenous (i.v.) administration of medications. These events are necessary for any success of emergency cardiovascular care. They are linked in a chain of survival. The links in the adult chain of survival are: early access; early CPR; early defibrillation; and early acute cardiac life support. The 'Utstein style', recently introduced, represents a standard of practice both inside and outside hospital with recommended guidelines for the uniform reporting of clinical data from the patient suffering cardiac arrest. According to the concept of the chain of survival, the Utstein style delineates time and establishes a set of core and supplemental times to be recorded that provide important characteristics of the response of victims of cardiac arrest.

Background and objective: Similar doses of ketamine are employed in regional and general anaesthesia. In contrast to commonly used local anaesthetic agents, accidental systemic application of local anaesthetic doses of ketamine will not result in seizure, dysrhythmia or cardiovascular depression. However, there is some doubt about the quality of regional analgesia induced by ketamine. As human sodium channels constitute an important molecular target of local anaesthetics, the study was designed to establish concentration-dependent effects of ketamine on conductance, steady-state activation and steady-state inactivation of human neuronal sodium channels. This information — that has, so far, not been published — will help to characterize further local anaesthetic properties of ketamine.

Methods: Whole-cell patch-clamp recordings were made of sodium channels natively expressed in human neuroblastoma SH-SY5Y cells.

Results: The sodium channels activated at a threshold of −60 mV and exhibited a maximal peak current at −10 mV. The voltage of half-maximal activation was −20 mV. The Na+ currents depended on the prepulse potential. The voltage of half-maximal inactivation was —80 mV. Ketamine inhibited the sodium conductance in a concentration-dependent manner (IC50 = 1140 µmol). A concentration-dependent hyperpolarizing shift of both steady-state activation and steady-state inactivation accounted for at most 5 mV.

Conclusions: The effects of ketamine on these human ion channels occur at clinical concentrations. They are consistent with the local anaesthetic action of ketamine. Whether ketamine helps to decrease the incidence of severe side-effects during regional anaesthesia needs to be addressed in further clinical studies.

Background and objective: Isoflurane is a chiral, volatile anaesthetic with low metabolic rate (0.17%) that is routinely administered in its racemic form. Knowledge about the distribution of the enantiomers in human beings may give some important information about the understanding of the mechanisms of volatile anaesthetics.

Methods: Blood samples were drawn immediately after tracheal extubation and daily up to 8 days postoperatively from patients undergoing general anaesthesia with isoflurane racemate. The enantiomer enrichment of isoflurane was determined by headspace gas chromatography-mass spectrometry.

Results: At all time points, there was a statistically significant accumulation of the S(+) enantiomer in blood, especially at days 2 (52.01%) and 7 (52.1%). Separate analysis of obese patients or in a small group of patients with co-existing lung disease did not show any difference to the total population. In addition, duration of anaesthesia did not influence the enantiomer concentrations.

Conclusions: We suggest that a slower association and dissociation rate is responsible for the S(+) enrichment.

Background and objective: The study was conducted to compare the standard intravenous route with the intranasal route of desmopressin application and to establish the best time for initiating treatment with desmopressin with the use of the Born test and the PFA 100®-Analyzer for monitoring the therapeutic effect.

Methods: Thirty healthy volunteers (ASA I) with no known bleeding disorder were randomly assigned to an intravenous or an intranasal group in a cross-over design fashion. After obtaining baseline values, the volunteers were given 500 mg aminosalicylic acid for 3 days. On day 4, platelet function tests were performed and desmopressin (0.3 μg kg−1 body weight) was administered either intravenously or intranasally. Born tests (aggregation after stimulation with epinephrine and collagen) were conducted at 30 and 240 min, and PFA 100® bleeding time measurements were conducted at 30, 120 and 240 min after desmopressin administration. Wilcoxon signed rank sum tests or non-parametric ANOVA for repeated measures were used for statistical evaluation.

Results: All volunteers showed a marked decreased platelet function in the Born test (especially if stimulation with epinephrine was used) and an increased PFA 100® bleeding time after treatment with aminosalicylic acid. Platelet function was improved by intravenous as well as intranasal application of desmopressin (P < 0.001) after 30 min. The effect diminished after 4 h in both groups.

Conclusions: Intravenous as well as intranasal desmopressin improved platelet function in healthy volunteers with aminosalicylic acid-induced platelet dysfunction at least 30 min after application. The effect lasts up to 4 h.

Background and objective: The effect of anaesthesia and surgery on gastric emptying is not constant, and this has not been previously studied in patients undergoing thoracotomy for lung resection with a bupivacaine-fentanyl epidural infusion for analgesia. There are important implications in this group of patients with regards to the recommencement of important oral medication as well as the risks of aspiration of gastric contents. The study examined gastric emptying in these patients until the second postoperative day.

Methods: In a prospective repeated measures study, the effect of fentanyl-bupivacaine epidural analgesia at the mid-thoracic level on gastric emptying was assessed in 11 patients undergoing thoracotomy for lung resection. Gastric emptying was measured using a paracetamol absorption technique. Patients acted as their preoperative controls and were assessed 4 h postoperatively and on the second postoperative day.

Results: The mean (SEM) maximum plasma paracetamol concentration was 204.6 (20.4) μmol L−1 before operation, 61 (9.5) μmol L−1 4 h postoperatively and 114.3 (22.6) μmol L−l on the second postoperative day. Mean (SEM) paracetamol absorption at 120 min was 15 638 (1441) μmol min L−l preoperatively, 5731 (821) μmol min L−l4 h postoperatively and 9325 (1759) μmol min L−l on the second postoperative day. Postoperative values were significantly (P < 0.005) less than the preoperative values.

Conclusions: After thoracotomy, gastric emptying was delayed until at least the second postoperative day in patients receiving mid-thoracic fentanyl-bupivacaine epidural analgesia.

Background and objective: To investigate the interactions of postoperative pain and endocrine stress response, three groups of 21 patients each with total knee arthroplasty were compared in a randomized, prospective design. For postoperative pain management, a three-in-one block, an epidural catheter analgesia or an intravenous patient-controlled analgesia was used.

Methods: After standardized balanced anaesthesia, the pain intensity was measured by a visual analogue scale (VAS). For detection of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone and cortisol in the plasma, blood samples were taken at six time points before and up to 180 min after the start of pain therapy. In addition, systolic arterial pressure, heart rate, partial arterial oxygen saturation, nausea, vomiting and satisfaction of the patients were recorded.

Results: Within 15 min after the start of pain therapy, VAS in all groups was similarly reduced from >40 mm to a range <10 mm (P < 0.001). Initially, all endocrine stress variables exceeded the normal range. Epidural anaesthesia led to a significant decrease of epinephrine and norepinephrine concentrations, while an increase was observed in the group with patient-controlled analgesia, and the decrease in patients with the three-in-one block was less than in patients receiving epidural anaesthesia (P = 0.001). Differences in antidiuretic hormone, adrenocorticotropic hormone and cortisol were less pronounced. Systolic arterial pressure decreased significantly in all groups, particularly in patients with epidural anaesthesia. Partial arterial oxygen saturation and the incidence of nausea and vomiting were comparable. All patients were satisfied with the methods used.

Conclusions: All methods of pain management led to sufficient analgesia, but they were not accompanied by an adequate reduction in endocrine stress response. Thus, postoperative pain is only a secondary stressor and sufficient analgesia with subjective well-being does not prove a stress-free state. With regard to the reduction of sympathoadrenergic stress response, epidural anaesthesia is superior to the three-in-one block and patientcontrolled analgesia. Epidural anaesthesia is recommended particularly for high-risk patients with hypertension, coronary heart disease and diabetes mellitus. In these patients, the reduction of a ‘hidden’ endocrine stress response in addition to prevention of pain is of special interest.

Background and objective: We assessed the analgesic efficacy of postoperative epidural infusions of ropivacaine 0.1 and 0.2% combined with sufentanil 1 μg mL−1 in a prospective, randomized, double-blinded study.

Methods: Twenty-two ASA I—III patients undergoing elective total-knee replacement were included. Lumbar epidural blockade using ropivacaine 0.75% was combined with either propofol sedation or general anaesthesia for surgery. After surgery, the epidural infusion was commenced. Eleven patients in each group received either an epidural infusion of ropivacaine 0.1% with 1 μg mL−1 sufentanil (Group 1) or ropivacaine 0.2% with 1 μg mL−1 sufentanil (Group 2) at a rate of 5–9 mL h−1. All patients had access to intravenous pirinatrimide (piritramide) via a patient-controlled analgesia (PCA) device.

Results: Motor block was negligible for the study duration in both groups. There was no significant difference with the 100 mm visual analogue scale (VAS) scores, with the consumption of rescue analgesia or with patient satisfaction. Patients in Group 1 experienced significantly less nausea (P < 0.05) than those in Group 2. Both treatment regimens provided effective postoperative analgesia with only a minimal use of supplemental opioid PCA.

Conclusions: We recommend the use of ropivacaine 0.1% with 1 μg mL−1 sufentanil for postoperative analgesia after total knee replacement as it provides efficient pain relief with no motor block of the lower limbs. In addition, compared with 0.2% ropivacaine with sufentanil, the mixture reduces local anaesthetic consumption without compromise in patient satisfaction or VAS scores. Patients even experience less nausea.

Background and objective: Although combined spinal and epidural anaesthesia is efficient and easy to perform, the technique can be a double-edged sword having the potential risk that an increased flux of drugs across the meninges through the hole made in it may lead to severe adverse effects. The aim was to compare the incidence of adverse events when an epidural injection of morphine was given after combined spinal and epidural anaesthesia or after epidural anaesthesia.

Methods: Fifteen patients had an epidural catheter inserted at the L2–3 interspace, and then a spinal block administered via the L3–4 interspace. Another 15 patients only had an epidural catheter inserted. After the onset of spinal or epidural anaesthesia had been confirmed, morphine 2 mg was injected into the epidural space, and a continuous epidural infusion of morphine was started. At the end of the operation and at 4, 8 and 12 h after the administration of epidural morphine and on the next day, the following variables were examined: blood pressure, heart rate, respiratory rate, arterial blood-gas analysis, visual analogue scale pain scores, nausea/ vomiting scores, and pruritus scores.

Results: In the study population, the epidural injection of morphine was not associated with a significantly higher incidence of adverse events when given after spinal anaesthesia than after epidural anaesthesia.

Conclusions: The adverse effects associated with epidural morphine given after spinal anaesthesia did not increase significantly when a 27-G Whitacre needle was used. Thus, the morphine flux through the meningeal hole into the cerebrospinal fluid was trivial.

Background and objective: Cardiovascular and mental stress in dental patients with phobias about dentistry may be reduced by propofol sedation. We tested the hypothesis that even low doses of propofol may have effects on body temperatures in male volunteers.

Methods: Six healthy male volunteers were given propofol over 28 min with the following infusion rates: 8 mg kg−1 h−1 for the first 3 min, 4 mg kg−1 h−1 for the next 10 min, and 2 mg kg−1 h−1 for the final 15 min. Body temperatures were measured at five locations: tympanic membrane, forehead, forearm, dorsum of the hand and fingertip. Thermoregulatory vasoconstriction was evaluated using the forearm minus fingertip temperature gradient.

Results: Tympanic membrane and forehead temperatures began to decrease at 10 and 20 min, respectively, after the start of the propofol infusion, and reached a minimum at 30 min (tympanic −0.5 ± 0.2°C) and 40 min (forehead −0.6 ± 0.2°C), respectively. Peripheral skin temperatures showed an increase between 10 and 30 min in the forearm and fingertip and between 20 and 30 min in the dorsum of the hand. After 30 min, a decrease in peripheral skin temperatures was observed. The forearm minus fingertip temperature gradient changed from negative to positive after 40 min, and increased continuously thereafter (baseline −0.3 ± 0.4°C, 90 min: 6.5 ± 1.6°C).

Conclusions: A low dose of propofol impairs tonic thermoregulatory vasoconstriction and induces heat redistribution from the core to the periphery.

Background and objective: A new posterior approach to the sciatic nerve in the subgluteal region was developed. We describe our clinical experiences on 135 consecutive patients.

Methods: All blocks were performed with a nerve stimulator (stimulation frequency 2 Hz; intensity from 1 reduced to ≤0.5 mA before application). A line was drawn from the greater trochanter to the ischial tuberosity of the femur; then, from the mid-point of this line, a second line was drawn perpendicularly and extended caudally for 4 cm: the end of this line represented the entry point of the needle. Sciatic stimulation was elicited at ≤0.5 mA; then ropivacaine 0.75% 20 mL was injected. An independent observer recorded the time from needle insertion to successful sciatic nerve stimulation (performance time), the depth of appropriate sciatic stimulation and the number of needle redirections, as well as the quality of nerve block, the discomfort during the procedure and patient acceptance.

Results: The performance time was 41 ± 25 s (mean ± SD) and the mean (SD) depth at which the sciatic nerve stimulation was found was 45 ± 10 mm. The median (range) number of needle redirections required to find the proper sciatic stimulation was 2 (1–5). The tibial response was observed in 77 patients (57%), while the common peroneal response was observed in 58 patients (43%). The degree of discomfort reported was very low and only 16 patients (12%) reported severe pain during placement of the block. The onset time (mean ± SD) of sensory and motor block was 7 ± 4 and 17 ± 13 min respectively, and the surgical procedure was completed with only the peripheral nerve block in 127 patients (94%). The same anaesthesia procedure was acceptable by 127 patients (94%) and only eight patients (6%) would prefer a different anaesthesia technique in the future.

Conclusions: The study demonstrated that the sciatic nerve can be easily blocked using this new posterior subgluteal approach, suggesting that it represents a safe and effective alternative to block the sciatic nerve at a proximal level, with the potential for reducing the discomfort experienced by the patient during block placement.