We compared heart rate dynamics during surgical levels of propofol and sevoflurane anaesthesia in a highly standardized setting.

We recorded electrocardiography from 24 anaesthetized healthy male subjects. In the first parallel part of the study, the subjects were anaesthetized either with sevoflurane (n = 8) or propofol (n = 8) targeted to match 1.0, 1.5 and 2.0 minimal alveolar concentration/effective concentration 50. In the second part, a separate group (n = 8) underwent four different anaesthetic regimens targeted to bispectral index 40: sevoflurane alone, sevoflurane + 70% nitrous oxide, propofol alone and propofol + 70% nitrous oxide. The electrocardiography data were analysed using conventional time and frequency domain methods, and the approximate entropy method, which estimates the complexity of the data.

The induction of anaesthesia was followed by an overall reduction of heart rate variability, evident in all frequency bands in the spectral analysis, and also in the time domain measures. Approximate entropy decreased at 1 effective concentration 50 with propofol and at 2 minimal alveolar concentration with sevoflurane. In the second part of the study, the time domain variables and high-frequency spectral power were all similarly reduced by sevoflurane and propofol anaesthesia, with and without nitrous oxide. Approximate entropy tended to decrease during propofol anaesthesia.

Hypnotic levels of sevoflurane and propofol anaesthesia suppressed the heart rate variability measured using conventional analysis methods. Deeper surgical levels of anaesthesia also reduce the complexity of heart rate variability.

Arterial oxygenation may be compromised in morbidly obese patients undergoing bariatric surgery. The aim of this study was to evaluate the effect of a vital capacity manoeuvre (VCM), followed by ventilation with positive end-expiratory pressure (PEEP), on arterial oxygenation in morbidly obese patients undergoing open bariatric surgery.

Fifty-two morbidly obese patients (body mass index >40 kg m−2) undergoing open bariatric surgery were enrolled in this prospective and randomized study. Anaesthesia and surgical techniques were standardized. Patients were ventilated with a tidal volume of 10 mL kg−1 of ideal body weight, a mixture of oxygen and nitrous oxide (FiO2 = 40%) and respiratory rate was adjusted to maintain end-tidal carbon dioxide at a level of 30–35 mmHg. After abdominal opening, patients in Group 1 had a PEEP of 8 cm H2O applied and patients in Group 2 had a VCM followed by PEEP of 8 cm H2O. This manoeuvre was defined as lung inflation by a positive inspiratory pressure of 40 cm H2O maintained for 15 s. PEEP was maintained until extubation in the two groups. Haemodynamics, ventilatory and arterial oxygenation parameters were measured at the following times: T0 = before application of VCM and/or PEEP, T1 = 5 min after VCM and/or PEEP and T2 = before abdominal closure.

Patients in the two groups were comparable regarding patient characteristics, surgical, haemodynamic and ventilatory parameters. In Group 1, arterial oxygen partial pressure (PaO2) and arterial haemoglobin oxygen saturation (SaO2) were significantly increased and alveolar-arterial oxygen pressure gradient (A-aDO2) decreased at T2 when compared with T0 and T1. In Group 2, PaO2 and SaO2 were significantly increased and A-aDO2 decreased at T1 and T2 when compared with T0. Arterial oxygenation parameters at T1 and T2 were significantly improved in Group 2 when compared with Group 1.

The addition of VCM to PEEP improves intraoperative arterial oxygenation in morbidly obese patients undergoing open bariatric surgery.

This prospective, double-blind, randomized, placebo-controlled study was designed to determine the efficacy of dexmedetomidine compared with lidocaine in reducing the pain of propofol and rocuronium injection pain.

One hundred and fifty patients, scheduled for elective surgery with general anaesthesia, were divided into five groups: saline (Group 1), dexmedetomidine 0.25 μg kg−1 (Group 2), lidocaine 0.5 mg kg−1 (Group 3), dexmedetomidine 0.25 μg kg−1 plus lidocaine 0.25 mg kg−1 (Group 4) or dexmedetomidine 0.25 μg kg−1 plus lidocaine 0.5 mg kg−1 (Group 5) were administered at a rate of 0.5 mL s−1 after tourniquet application. The occlusion was released after 1 min and 5 mL of propofol was injected over 20 s. Pain was evaluated by use of a 10-point verbal analogue scale. Then, the rest of the induction dose of propofol, 3 mL of saline bolus and 0.6 mg kg−1 of rocuronium, was injected. The response to injection of rocuronium was assessed with a four-point scale (0–3).

Groups 1 and 2 were found to have higher propofol injection pain scores than Groups 3, 4 and 5 (P < 0.05). When the study groups were compared according to the overall incidence of withdrawal movements due to rocuronium (⩾1 response) in Groups 1, 2, 3, 4 and 5, they were different (86.7%, 60%, 36.7%, 50% and 40%, respectively) (P < 0.05). Except Group 1, there was no significant difference between the groups according to incidence of withdrawal movement after rocuronium injection (P = 0.325).

Pretreatment with dexmedetomidine is not effective in reducing injection pain of propofol, but may attenuate the hand withdrawal associated to rocuronium, as lidocaine does.

Levobupivacaine in combination with sufentanil may be used for labour or postoperative regional analgesia. The risk of bacterial growth within these contained solutions for several hours at room temperature is unknown. We investigated the in vitro antimicrobial effect of levobupivacaine and sufentanil against common micro-organisms encountered during regional anaesthesia.

Standardized suspensions of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli were incubated for 1, 3, 6 and 24 h at 25°C, with saline (as control), sufentanil 0.5 or 0.75 μg mL−1, levobupivacaine hydrochloride 5.6 mg mL−1 and concentrations of 1.4, 2.8 and 5 mg mL−1 of levobupivacaine hydrochloride with sufentanil 0.5 μg mL−1. Colony counts were compared after 24 h incubation at 37°C.

No bacterial growth was observed on any bacterial strain for any solution tested throughout the experiment.

Our results suggest that solutions of levobupivacaine combined with sufentanil may be used for 24 h at room temperature during regional anaesthesia with no risk of bacterial growth.

To compare intubation conditions and time-course of action of rocuronium and mivacurium for day case anaesthesia.

Fifty ASA I or II patients were enrolled. Anaesthesia was induced with propofol using a target controlled infusion system (target 6–8 μg mL−1) and sufentanil (0.25 μg kg−1). It was maintained with propofol (target 3.5–4.5 μg mL−1) and 50% nitrous oxide in oxygen. Muscle relaxation was achieved with either mivacurium (0.15 mg kg−1) or rocuronium (0.3 mg kg−1). Neuromuscular transmission was monitored and recorded continuously by acceleromyography using a TOF-WATCH SX (Biometer™/; Denmark) with supramaximal train-of-four stimulation of the ulnar nerve. Tracheal intubation was carried out by an experienced anaesthetist blinded to the type of the muscle relaxant. Intubation conditions were evaluated according to a standard scheme (ease of laryngoscopy, position of vocal cords, airway reaction and limb movements).

Intubation conditions were good or excellent for both mivacurium 0.15 mg kg−1 (good = 8%; excellent = 92%) and rocuronium 0.3 mg kg−1 (excellent = 100%). Times to maximum blockade and clinical duration were not different.

There is no significant difference between mivacurium and rocuronium concerning the onset and the recovery of muscle relaxation. Rocuronium is an alternative to mivacurium for short procedures, without the risk of unexpected prolonged relaxation due to a possible defect in plasma cholinesterase.